2D PdAg Alloy Nanodendrites for Enhanced Ethanol Electroxidation

Solvothermal synthesis of PdCu nanorings with high catalytic performance for alcohol electrooxidation

Two-dimensional (2D) Pd-based nanostructures with a high active surface area and a large number of active sites are commonly used in alcohol oxidation research, whereas the less explored ring structure made of nanosheets with large pores is of interest. In this study, we detail the fabrication of PdCu nanorings (NRs) featuring hollow interiors and low coordinated sites using a straightforward solvothermal approach. Due to increased exposure of active sites and the synergistic effects of bimetallics, the PdCu NRs exhibited superior catalytic performance in both the ethanol oxidation reaction (EOR) and the ethylene glycol oxidation reaction (EGOR). The mass activities of PdCu NRs for EOR and EGOR were measured at 7.05 A/mg and 8.12 A/mg, respectively, surpassing those of commercial Pd/C. Furthermore, the PdCu NRs demonstrated enhanced catalytic stability, maintaining higher mass activity levels compared to other catalysts during stability testing. This research offers valuable insights for the development of efficient catalysts for alcohol oxidation.

Printable and filament-drawable PDMS based adhesive assisted manufacturing of highly conductive copper micro-patterns

Manufacturing of copper micro-patterns is crucial in electronics for its utilization as high conductivity transparent conductive films (TCFs) and circuits. In the preparation process of current TCFs, a plethora of materials have emerged that can replace traditional indium tin oxide (ITO). However, even for the most promising metal-based nanowire materials, there are issues such as high cost, complex welding, and high contact resistance. To address these problems, this paper proposes a printable and filament-drawable polydimethylsiloxane (PDMS)-based adhesive, which, through a novel additive patterning technology, efficiently and economically manufactures self-welding copper micro-meshes and circuits. The adhesive can be processed into micro-patterns through printing and filament drawing, on which ionic Ag can be in situ reduced and anchored, thereby eliminating the need for tedious pre- and post-treatment steps. The fully exposed Ag particles dramatically minimize the usage of precious metal catalyst, thus efficiently catalyzing electroless copper deposition (ECD) reaction. Highly conductive (1.03 × 107 S m-1) copper circuits can be fabricated on the printed adhesive patterns, exhibiting versatile applicability to diverse substrates. Highly precise copper micro-meshes (∼50 μm) can be fabricated on the filament networks drawn by the adhesive. The copper meshes undergo complete self-welding at junctions during the ECD process, thus exhibiting ultra-low square resistance of 0.45 Ω sq-1 while maintaining a high transmittance of 82.2 %. This is far superior to most of TCFs in published literature.

High-Entropy PdRhFeCoMo Metallene With High C1 Selectivity and Anti-Poisoning Ability for Ethanol Electrooxidation

The urgent demand for designing highly efficient electrocatalysts for ethanol oxidation reaction (EOR) with elevated C1 selectivity, robust anti-poisoning capability, and high mass activity presents a formidable challenge. Herein, a novel two-dimentional (2D) high-entropy PdRhFeCoMo metallene (PdRhFeCoMo HEM) electrocatalyst is successfully synthesized via a mild one-step solvothermal method. The PdRhFeCoMo HEM, characterized by intentionally designed multi-metallic ensembles and ultra-thin graphene-like structures, delivers an impressive mass activity of 7.47 A mgPd+Rh -1 and specific activity of 25.5 mA cm-2. Furthermore, it can retain a mass activity of 0.56 A mgPd+Rh -1 after undergoing 20000 s of continuous testing, demonstrating outstanding resistance to poisoning. More significantly, the PdRhFeCoMo HEM demonstrates an elevated capacity for C─C bond cleavage with a superior C1 selectivity of up to 84.12%. In situ spectroscopy analysis, combined with theoretical calculations, reveals that the deliberate design of components and structures effectively regulate the electronic properties of the Pd site, thereby enhancing the adsorption of reactant and reducing the reaction barrier of the C1 pathway. Finally, a flexible solid-state ethanol fuel cell assembled by PdRhFeCoMo HEM presents a maximum power density of 20.1 mW cm-2 and can operate continuously by repeatedly adding ethanol fuel.

Freestanding Penta-Twinned Pd-Ag Nanosheets

2D metal nanosheets have attracted significant attention as efficient catalysts for various important chemical reactions. However, the development of metal nanosheets with controlled compositions and morphologies has been slow due to the challenges associated with synthesizing thermodynamically unfavorable 2D structures. Herein, we report a synthesis route of freestanding Pd-Ag penta-twinned nanosheets (Pd-Ag ptNSs) with distinct 5-fold twin boundaries. Through the coreduction of Ag and Pd precursors on presynthesized Pd ptNSs, Ag could be homogeneously alloyed with Pd, leading to the formation of well-defined Pd-Ag ptNSs. The promotional effects of the bimetallic composition, 2D structure, and twin boundaries on catalysis were studied by using Pd-Ag ptNS-catalyzed H2 production from formic acid decomposition as a model reaction. Notably, the catalytic activity of the Pd-Ag ptNSs drastically outperformed those of monometallic, bimetallic, and 3D counterparts, such as Pd ptNSs, Pd-Ag nanosheets without a TB, and Pd-Ag octahedral nanocrystals, demonstrating the promising potential of the integration of twin boundaries and multiple compositions in the development of high-performance 2D nanocatalysts.

Selective exposure of (111) crystal plane in Pd49Ag30Te4 by Tb doping to weaken Pd - C bond and promote electroreduction of CO2 to CO

Employing electric energy to convert carbon dioxide (CO2) into valuable small molecules is a potentially practical method in energy storage and greenhouse gas alleviation. A huge challenge for electrocatalytic CO2 reduction is to reduce overpotential to improve energy efficiency. Herein, we demonstrate that doping alloy Pd49Ag30Te4 (PAT) with rare-earth element Tb is beneficial for selective exposure of (111) crystal plane, which is a highly active crystal plane for producing carbon monoxide (CO). The as-prepared Tb2.9PAT exhibited high electrocatalytic performance with 95.7 % CO faradic efficiency at - 0.8 V (vs RHE), far exceeding that of PAT, and coupled with good durability. In situ spectral study and theoretical calculations disclose that the introduction of Tb regulates the d-band center of PAT alloy, weakens the Pd - C bonding ability, and promotes the desorption of *CO in the rate-determining step. This study provides a method for doping induced selective exposure of crystal face, which provides new idea for improving catalytic performance.

Ultrasensitive self-powered biosensor with facile chemical signal amplification strategy using hydrogen peroxide-triggered silver oxidation reaction

The amplification strategies used for self-powered biosensor based on biofuel cell (BFC-SPB) need to be further developed. Because the currently developed strategies utilized the complicated hybridization of DNA or poorly readable current signal of capacitors for amplification, which limits the practical application in public health emergencies. Here, we present a facile chemical amplification strategy for BFC-SPB. The 5-min amplification was triggered by simply adding H2O2 solution dropwise to the sensing cathode after the formation of the immune sandwich. The Ag NP of immunoprobe were oxidized to Ag(I), which can be served as the electron acceptor of the cathode. The amount of immunoprobe was positively correlated with that of the antigen, resulting in corresponding and high concentration of Ag(I) after the amplification, which enhanced the ability of the cathode as the electron acceptor. Meanwhile the glucose oxidation reaction (GOR) was performed on the bioanode modified with glucose oxidase (GOx). After assembling the bioanode and sensing cathode, the open circuit voltage of the BFC-SPB, measured by digital multimeter, distinctly rised with the elevated concentration of the antigen. To demonstrate the proof of concept, immunoglobulin G (IgG), selecting as a model analyte, was sensitively detected using this method. Result indicated that the limit of detection was 4.4 fg mL-1 (0.03 amol mL-1) in the linear range of 1 pg mL-1-10 μg mL-1. This work initiates a brand-new way of chemical amplification strategy for BFC-SPB, and offers a promising platform for practical applications.

Unconventional Electrocatalytic CO Conversion to C2 Products on Single-Atomic Pd-Agn Sites

The electrochemical reduction of CO or CO2 into C2+ products has mostly been focused on Cu-based catalysts. Although Ag has also been predicted as a possible catalyst for the CO-to-C2+ conversion from the thermodynamic point of view, however, due to its weak CO binding strength, CO rapidly desorbs from the Ag surface rather than participates in deep reduction. In this work, we demonstrate that single-atomic Pd sites doped in Ag lattice can tune the CO adsorption behavior and promote the deep reduction of CO toward C2 products. The monodispersed Pd-Agn sites enable the CO adsorption with both Pd-atop (PdL) and Pd-Ag bridge (PdAgB) configurations, which can increase the CO coverage and reduce the C-C coupling energy barrier. Under room temperature and ambient pressure, the Pd1Ag10 alloy catalyst exhibited a total CO-to-C2 Faradaic efficiency of ~37 % at -0.83 V, with appreciable current densities and electrochemical stability, thus featuring unconventional non-Cu electrocatalytic CO-to-C2 conversion capability.

AgI Precipitation Induced Polarity Reversal with Formation of Z-Type Heterojunction for Photoelectrochemical Sensing

Regulating photocurrent polarity is highly attractive for fabricating photoelectrochemical (PEC) biosensors with improved sensitivity and accuracy in practical samples. Here, a new approach that adopts the in situ generated AgI precipitate and AgNCs to reversal Bi2WO6 polarity with formation of Z-type heterojunction was proposed for the first time, which coupled with a high-efficient target conversion strategy of exonuclease III (Exo III)-assisted triple recycling amplification for sensing miRNA-21. The target-related DNA nanospheres in situ generated on electrode with loading of plentiful AgI and AgNCs not only endowed the photocurrent of Bi2WO6 switching from the anodic to cathodic one due to the changes in the electron transfer pathway but also formed AgI/AgNCs/Au/Bi2WO6 Z-type heterojunction to improve the photoelectric conversion efficiency for acquiring extremely enhanced PEC signal, thereby significantly avoiding the problem of high background signal derived from traditional unidirectional increasing/decreasing response and false-positive/false-negative. Experimental data showed that the PEC biosensor had a low detection limit down to 0.085 fM, providing a new polarity-reversal mechanism and expected application in diverse fields, including biomedical research and clinical diagnosis.

A novel composite electrode with multiple pore structures for efficient treatment of heavy metal ions in capacitive deionization

Multiple porous carbon materials have great promise and potential in the capacitive deionization (CDI) field. Specific surface area (SSA), pore size distribution, and preparation method of CDI electrode materials are essential for the treatment of heavy metal ions. In this work, PPy composited porous carbon electrodes (hypercrosslinked polymers/polypyrrole, HCPs/PPy) were obtained by one-step crosslinked carbonization preparation and electro-deposition. The diverse pore structure gives the composite electrode a large SSA and excellent adsorption performance. HCPs/PPy-4 gives a high SSA of 251.26 m2/g. In the CDI process, the adsorption capacity of HCPs/PPy-4 for Fe3+, Cu2+, Pb2+, and Ag+ is 20.69 mg/g, 37.81 mg/g, 26.86 mg/g, and 40.95 mg/g. The negative electrode recoveries for the adsorption of the four ions were reached 81.2%, 89.2%, 85.5%, and 100%, respectively. It indicates that HCPs/PPy is a novel and potentially porous carbon electrode for high-performance CDI.

D-Band Engineering in Pd-Based Nanowire Networks for Further Enhancement in Ethanol Electrooxidation Reaction

The development of highly efficient electrocatalysts for the ethanol oxidation reaction (EOR) is essential for the commercialization of direct ethanol fuel cells, yet challenges remain. In this study, a one-pot solution-phase method to synthesize Pd nanowire networks (NNWs) with very high surface-to-volume ratio having numerous twin and grain boundaries is developed. Using the same method, the Pd lattice is further engineered by introducing Ag and Cu atoms to produce AgPd, and CuPd alloy structure which significantly shifts the Pd d-band center upward and downward, respectively due to strain and ligand effects. Theoretical analysis employing density functional theory (DFT) demonstrates that such modification of the d-band center significantly influences the adsorption energies of reactants on the catalytic surface. Owing to their notably high surface-to-volume ratio and the presence of multiple twin and grain boundaries, Pd NNWs demonstrate significantly enhanced electrocatalytic activity toward EOR, ≈7.2 times greater than that of commercial Pd/C. Remarkably, compared to Pd NNWs, AgPd, and CuPd NNWs display enlarged and reduced electrocatalytic activity toward EOR, respectively. Specifically, Ag4Pd7 NNWs achieve a remarkable mass activity of 9.00 A mgpd -1 for EOR, which is 13.6 times higher than commercial Pd/C.

Ultra-Large Two-Dimensional Metal Nanowire Networks by Microfluidic Laminar Flow Synthesis for Formic Acid Electrooxidation

Despite the great research interest in two-dimensional metal nanowire networks (2D MNWNs) due to their large specific surface area and abundance of unsaturated coordination atoms, their controllable synthesis still remains a significant challenge. Herein, a microfluidics laminar flow-based approach is developed, enabling the facile preparation of large-scale 2D structures with diverse alloy compositions, such as PtBi, AuBi, PdBi, PtPdBi, and PtAuCu alloys. Remarkably, these 2D MNWNs can reach sizes up to submillimeter scale (~220 μm), which is significantly larger than the evolution from the 1D or 3D counterparts that typically measure only tens of nanometers. The PdBi 2D MNWNs affords the highest specific activity for formic acid (2669.1 mA mg-1) among current unsupported catalysts, which is 103.5 times higher than Pt-black, respectively. Furthermore, in situ Fourier transform infrared (FTIR) experiments provide comprehensive evidence that PdBi 2D MNWNs catalysts can effectively prevent CO* poisoning, resulting in exceptional activity and stability for the oxidation of formic acid.

Freestanding Penta-Twinned Palladium Nanosheets

Control over the morphology of nanomaterials to have a 2D structure and manipulating the surface strain of nanostructures through defect control have proved to be promising for developing efficient catalysts for sustainable chemical and energy conversion. Here a one-pot aqueous synthesis route of freestanding Pd nanosheets with a penta-twinned structure (PdPT NSs) is presented. The generation of the penta-twinned nanosheet structure can be succeeded by directing the anisotropic growth of Pd under the controlled reduction kinetics of Pd precursors. Experimental and computational investigations showed that the surface atoms of the PdPT NSs are effectively under a compressive environment due to the strain imposed by their twin boundary defects. Due to the twin boundary-induced surface strain as well as the 2D structure of the PdPT NSs, they exhibited highly enhanced electrocatalytic activity for oxygen reduction reaction compared to Pd nanosheets without a twin boundary, 3D Pd nanocrystals, and commercial Pd/C and Pt/C catalysts.

2D PtRhPb Mesoporous Nanosheets with Surface-Clean Active Sites for Complete Ethanol Oxidation Electrocatalysis

The development of active and selective metal electrocatalysts for complete ethanol oxidation reaction (EOR) into desired C1 products is extremely promising for practical application of direct ethanol fuel cells. Despite some encouraging achievements, their activity and selectivity remain unsatisfactory. In this work, it is reported that 2D PtRhPb mesoporous nanosheets (MNSs) with anisotropic structure and surface-clean metal site perform perfectly for complete EOR electrocatalysis in both three-electrode and two-electrode systems. Different to the traditional routes, a selective etching strategy is developed to produce surface-clean mesopores while retaining parent anisotropy quasi-single-crystalline structure without the mesopore-forming surfactants. This method also allows the general synthesis of surface-clean mesoporous metals with other compositions and structures. When being performed for alkaline EOR electrocatalysis, the best PtRhPb MNSs deliver remarkably high activity (7.8 A mg-1) and superior C1 product selectivity (70% of Faradaic efficiency), both of which are much better than reported electrocatalysts. High performance is assigned to multiple structural and compositional synergies that not only stabilized key OHads intermediate by surface-clean mesopores but also separated the chemisorption of two carbons in ethanol by adjacent Pt and Rh sites, which facilitate the oxidation cleavage of stable C─C bond for complete EOR electrocatalysis.

Recent advances of doping strategy for boosting the electrocatalytic performance of two-dimensional noble metal nanosheets

Benefiting from the ultrahigh specific surface areas, massive exposed surface atoms, and highly tunable microstructures, the two-dimensional (2D) noble metal nanosheets (NSs) have presented promising performance for various electrocatalytic reactions. Nevertheless, the heteroatom doping strategy, and in particular, the electronic structure tuning mechanisms of the 2D noble metal catalysts (NMCs) yet remain ambiguous. Herein, we first review several effective strategies for modulating the electrocatalytic performance of 2D NMCs. Then, the electronic tuning effect of hetero-dopants for boosting the electrocatalytic properties of 2D NMCs is systematically discussed. Finally, we put forward current challenges in the field of 2D NMCs, and propose possible solutions, particularly from the perspective of the evolution of electron microscopy. This review attempts to establish an intrinsic correlation between the electronic structures and the catalytic properties, so as to provide a guideline for designing high-performance electrocatalysts.

Stabilization of Pd0 by Cu Alloying: Theory-Guided Design of Pd3Cu Electrocatalyst for Anodic Methanol Carbonylation

Electrocatalytic carbonylation of CO and CH3OH to dimethyl carbonate (DMC) on metallic palladium (Pd) electrode offers a promising strategy for C1 valorization at the anode. However, its broader application is limited by the high working potential and the low DMC selectivity accompanied with severe methanol self-oxidation. Herein, our theoretical analysis of the intermediate adsorption interactions on both Pd0 and Pd4+ surfaces revealed that inevitable reconstruction of Pd surface under strongly oxidative potential diminishes its CO adsorption capacity, thus damaging the DMC formation. Further theoretical modeling indicates that doping Pd with Cu not only stabilizes low-valence Pd in oxidative environments but also lowers the overall energy barrier for DMC formation. Guided by this insight, we developed a facile two-step thermal shock method to prepare PdCu alloy electrocatalysts for DMC. Remarkably, the predicted Pd3Cu demonstrated the highest DMC selectivity among existing Pd-based electrocatalysts, reaching a peaked DMC selectivity of 93 % at 1.0 V versus Ag/AgCl electrode. (Quasi) in situ spectra investigations further confirmed the predicted dual role of Cu dopant in promoting Pd-catalyzed DMC formation.

One-pot Synthesis of PdCuAg and CeO2 Nanowires Hybrid with Abundant Heterojunction Interface for Ethylene Glycol Electrooxidation

Introducing CeO2 into Pd-based nanocatalysts for electrocatalytic reactions is a good way to solve the intermediate toxicity problem and improve the catalytic performance. Here we reported a simple strategy to synthesize the PdCuAg and CeO2 nanowires hybrid via a one-pot synthesis process under strong nanoconfined effect of specific surfactant as templates. Owing to the structural (ultrathin nanowires, abundant heterojunction/interfaces between metal and metal oxide) and compositional (Pd, Cu, Ag, CeO2) advantages, the hybrid showed significantly enhanced catalytic activity (6.06 A mgPd -1) and stability, accelerated reaction rate, and reduced activation energy toward electrocatalytic ethylene glycol oxidation reaction.

Nanoscale Design for High Entropy Alloy Electrocatalysts

Due to their distinctive physical and chemical characteristics, high entropy alloys (HEAs), a class of alloys comprising multiple elements, have garnered a lot of attention. It is demonstrated recently that HEA electrocatalysts increase the activity and stability of several processes. In this paper, the most recent developments in HEA electrocatalysts research are reviewed, and the performance of HEAs in catalyzing key reactions in water electrolysis and fuel cells is summarized. In addition, the design strategies for HEA electrocatalysts optimization is introduced, which include component selection, size optimization, morphology control, structural engineering, crystal phase regulation, and theoretical prediction, which can guide component selection and structural design of HEA electrocatalysts.

MOF-based Ag NPs/Co3O4 nanozyme for colorimetric detection of thiophanate-methyl based on analyte-enhanced sensing mechanism

Silver nanoparticles supported on metal-organic framework (ZIF-67)-derived Co3O4 nanostructures (Ag NPs/Co3O4) were synthesized via a facile in situ reduction strategy. The resulting materials exhibited pH-switchable peroxidase/catalase-like catalytic activity. Ag NP doping greatly enhanced the catalytic activity of Ag NPs/Co3O4 towards 3,3',5,5'-tetramethylbenzidine (TMB) oxidation and H2O2 decomposition which were 59 times (A652 of oxTMB) and 3 times (A240 of H2O2) higher than that of ZIF-67, respectively. Excitingly, thiophanate-methyl (TM) further enhanced the peroxidase-like activity of Ag NPs/Co3O4 nanozyme due to the formation of Ag(I) species in TM-Ag NPs/Co3O4 and generation of more radicals resulting from strong interaction between Ag NPs and TM. The TM-Ag NPs/Co3O4 nanozyme exhibited lower Km and higher Vmax values towards H2O2 when compared with Ag NPs/Co3O4 nanozyme. A simple, bioelement-free colorimetric TM detection method based on Ag NPs/Co3O4 nanozyme via analyte-enhanced sensing strategy was successfully established with high sensitivity and selectivity. Our study demonstrated that hybrid noble metal NPs/MOF-based nanozyme can be a class of promising artificial nanozyme in environmental and food safety applications.

Self-adhesive, surface adaptive, regenerable SERS substrates for in-situ detection of urea on bio-surfaces

Wearable SERS substrates have gained substantial attention for health monitoring and other applications. Current designs often rely on conventional polymer substrates, leading to discomfort and complexity due to the need of additional adhesive layers. To address the issues, we fabricate a flexible, uniform, ultrathin, transparent and porous SERS substrate via depositing Ag nanoparticles (AgNPs) onto the CdS nanowires (CdSNWs) grown on the surface of a prepared nanofilm (AgNPs-CdSNWs/nanofilm). Unlike the wearable SERS substrates reported in literature, the one presented in this work is self-adhesive to a variety of surfaces, which simplifies structure, enhances comfort and improves performance. Importantly, the new SERS substrate as developed is highly stable and reusable. Artificial sample tests revealed that the substrate showed a great enhancement factor (EF) of 4.2 × 107 and achieved a remarkable detection limit (DL) of 1.0 × 10-14 M for rhodamine 6G (R6G), which are among the highest records observed in wearable SERS substrates reported in literature. Moreover, the substrate enables at real-time and in-situ reliable monitoring of urea dynamics in human sweat and plant leaves, indicating its applicability for health analysis and in precision agriculture.

Chameleon-like Response Mechanism of Gold-Silver Bimetallic Nanoclusters Stimulated by Sulfur Ions and Their Application in Visual Fluorescence Sensing

Herein, 2-mercapto-5-benzimidazolesulfonate acid sodium salt dihydrate (MBZS)-protected gold-silver bimetallic nanoclusters, named MBZS-AuAg NCs, were synthesized. Interestingly, we found that MBZS-AuAg NCs solutions can exhibit different fluorescence color changes under sulfide stimulation. A series of modern analytical testing techniques were used to explore the interaction mechanism between MBZS-AuAg NCs and sulfide. Sulfide ions can not only cause MBZS-AuAg NCs to exhibit rich fluorescence color changes similar to those of a chameleon but also have four linear relationships between the response intensity and sulfide concentration. A wide-range sulfide fluorescence sensing platform was constructed based on four linear segments with different fluorescence color responses. This sensing platform can be directly used for the determination of S2- with a detection limit as low as 11 nM. The portable test paper based on MBZS-AuAg NCs can realize the visual and rapid detection of gaseous hydrogen sulfide with a detection limit of 100 ppb (v/v). The wide detection range of the proposed method not only allows it to be used as an alternative method for sulfide detection in environmental samples but also has potential applications in the rapid detection and early warning of hydrogen sulfide gas in industrial and mining scenarios.

Highly branched and ultrathin Au nanodendrites for reduction catalysis

Two-dimensional (2D) materials have garnered significant attention due to their distinctive physicochemical properties, with 2D noble metal nanodendrites being particularly intriguing in terms of their properties and functional prospects. However, the synthesis of ultrathin and highly branched gold nanodendrites (AuNDs) still poses challenges. In this study, we successfully achieved the synthesis of highly branched 2D AuNDs with a thickness of 4 nm by employing a carboxyl-functionalized C22-tailed surfactant along with the co-directing agent 2-mercaptonicotinic acid (2-MNA). The careful selection of specific thiol molecules such as 2-MNA is crucial for controlling the degree of branching and promoting the formation of ultrathin nanodendrites. Furthermore, we extended this method to synthesize alloy nanodendrites (AuAg NDs and AuCoAg NDs) using a similar approach. Due to their highly branched and ultrathin two-dimensional morphology, these prepared AuNDs exhibit excellent catalytic performance in the model reaction for 4-NP reduction. This thiol-induced synthesis strategy for AuNDs opens up new possibilities for designing other Au nanomaterials with an ultrathin morphology/structure.

Ultrathin PdPtP nanodendrites as high-activity electrocatalysts toward alcohol oxidation

PdPtP nanodendrites were prepared by a post-phosphating method. Due to their well-designed structure and composition, the EOR activity of the PtPdP NDs is significantly increased to 14.3 A mgPd+Pt-1, which is a significant improvement compared to commercial Pd/C catalysts. In addition, stability tests demonstrated their excellent catalytic activity and structural durability.

Concentration analysis of metal-labeled nanoplastics in different water samples using electrochemistry

Despite the threats posed by nanoplastics to the environment and human health, little was known about the occurrence, formation, migration, and environmental impacts of nanoplastics due to the lack of quantitative and sensitive detection techniques. In this work, an electrochemical strategy for the detection of nanoplastics based on Ag labeling was proposed. Positively charged silver ions were attached to negatively charged polystyrene nanoplastics (PSNPs), and then the silver ions on the surface of PSNPs were reduced to Ag by sodium borohydride. Subsequently, the concentration of PSNPs was determined by identifying the signal of Ag by differential pulse voltammetry. The method showed different sensitivity for PSNPs of different sizes (100, 367, 500 nm). For tap water samples, the reason for the change in Ag electrochemical signal was discussed. The sensitivity of the method to PSNPs in tap water was investigated. The feasibility of the method for environmental water samples was verified using spiked lake water and spiked seawater, and satisfactory recoveries (93-112 %) were obtained for PSNPs of different sizes and concentrations. This study provided a sensitive, low-cost, and simple method without complex instrumentation, which was important for the determination of PSNPs in environmental water samples.

Efficient self-cleaning and antibacterial ceramics with ultra-low doping and high exposure of silver

The secondary bacterial infection of COVID-19 is known to contribute significantly to mortality rates. Silver (Ag)-based antibacterial ceramics have emerged as a prominent solution for daily antibacterial applications, aiming to minimize the reliance on disinfectants while safeguarding human health. However, the fabrication of Ag-based antibacterial ceramics with low Ag content, high dispersion, and high exposure still faces challenges. In this work, an innovative method was proposed to doping Ag nanoparticles (Ag NPs) into glass ceramics (GC) via a "melt-freeze" method, then efficient and stable Ag-doped antibacterial ceramics (GC-xAg@BiOCl) were fabricated through facile in-situ HCl etching GC. Results indicate that the low Ag content (0.03 mol%) and high dispersion of Ag NPs are fully exposed and anchored on the surface, and constructed Schottky junction Ag/BiOCl contributed to antibacterial and photocatalytic activity. The degradation rates of norfloxacin and methylene blue by GC-0.25Ag@BiOCl can reach 71.0% and 55.3% under visible light irradiation, respectively. Moreover, The GC-0.25Ag@BiOCl exhibited significant antibacterial activity against Escherichia coli (E.coli) and Staphylococcus aureus (S. aureus), with E.coli at 7.3 log10 cfu/mL and S. aureus at 7.0 log10 cfu/mL completely inactivated under visible light irradiation. Additionally, the antibacterial mechanism and charge transfer mechanism were explored.

Hydrated alginate polysaccharide fabrics grafted with sliver nanocrystals for wearable thermal and health management

The creation of functional components with precise chemistries on carbohydrate polymers is of great significance for future wearable biomedicine and health management. Among various carbohydrate polymers, marine polysaccharide featured with antimicrobial, biodegradable and biocompatible properties is an ideal platform while the water-swelling nature makes it difficult to form stable interface. Here, well-dispersed silver nanoparticles have been in-situ assembled on hydrated alginate fabric (AF), involving chemical absorption of Ag ions and in-situ reduction of conductive Ag layer. Owing to the stable complex formed between Ag ions and carboxyl groups, the Ag-grafted AF exhibits superior Joule heating capability, including low operating voltage (1-3 V), high saturation temperature (63 °C), rapid response time (25 s) and outstanding durability against harsh conditions. Furthermore, the Ag-grafted AF demonstrates noticeable inhibition against E. coli and S. aureus as compared with the pristine AF. This work provides a rational strategy for the functionalization of hydrated polysaccharide and enables wearable thermotherapy devices for human health management.

Synthesis and Prospects of Holey Two-dimensional Platinum-group Metals in Electrocatalysis

Advanced electrocatalysts can enable the widespread implementation of clean energy technologies. This paper reviews an emerging class of electrocatalytic materials comprising holey two-dimensional free-standing Pt-group metal (h-2D-PGM) nanosheets, which are categorically challenging to synthesize but inherently rich in all the qualities necessary to counter the kinetic and thermodynamic challenges of an electrochemical conversion process with high catalytic efficiency and stability. Although the 2D anisotropic growth of typical nonlayered metal crystals has succeeded and partly improved their atom-utilization efficiency, regularly distributed in-planar porosity can further optimize three critical factors that govern efficient electrocatalysis process: mass diffusion, electron transfer, and surface reactivity. However, producing such advanced morphological features within h-2D-PGMs is difficult unless they are specially engineered using approaches such as templating or kinetic ramification during 2D growth or controlled etching of preformed 2D-PGM solids. Therefore, this review highlighting the successful fabrication of various porous PGM nanosheets and their electrocatalytic benefits involving smart nanoscale features could inspire next-generation scientific and technological innovations toward securing a sustainable energy future.

Interface Engineering and Boron Modification of Pd-B/Pd Hetero-Metallene Synergistically Accelerate Oxygen Reduction Catalysis

2D metallene possess high surface area and excellent electron transport capability, thus enabling efficient application in oxygen reduction reaction (ORR). However, the interface regulation and electronic structure optimization of metallene are still great challenges. Herein, Pd-B/Pd hetero-metallene is constructed by interface engineering and B modification strategies for efficient electrocatalytic ORR. The 2D configuration of Pd-B/Pd hetero-metallene exposes a large number of surface atoms and unsaturated defect sites, thus providing abundant catalytic active sites and exhibiting high electron mobility. More importantly, interface engineering and B modification synergistically optimizing the electronic configuration of the metallene system. This work not only provides an effective strategy for the rational regulation of the electronic configuration of metallene, but also offers a reference for the construction of efficient ORR catalysts.

Two-dimensional mesoporous metals: a new era for designing functional electrocatalysts

Two-dimensional (2D) mesoporous metals contribute a unique class of electrocatalyst materials for electrochemical applications. The penetrated mesopores of 2D mesoporous metals expose abundant accessible undercoordinated metal sites, while their 2D nanostructures accelerate the transport of electrons and reactants. Therefore, 2D mesoporous metals have exhibited add-in structural functions with great potential in electrocatalysis that not only enhance electrocatalytic activity and stability but also optimize electrocatalytic selectivity. In this Perspective, we summarize recent progress in the design, synthesis, and electrocatalytic performance of 2D mesoporous metals. Four main strategies for synthesizing 2D mesoporous metals, named the CO (and CO container) induced route, halide ion-oriented route, interfacial growth route, and metal oxide atomic reconstruction route, are presented in detail. Moreover, electrocatalytic applications in several important reactions are summarized to highlight the add-in structural functions of 2D mesoporous metals in enhancing electrochemical activity, stability, and selectivity. Finally, current challenges and future directions are discussed in this area. This Perspective offers some important insights into both fundamental investigations and practical applications of novel high-performance functional electrocatalysts.

A Comprehensive Review on Electrocatalytic Applications of 2D Metallenes

This review introduces metallenes, a cutting-edge form of atomically thin two-dimensional (2D) metals, gaining attention in energy and catalysis. Their unique physicochemical and electronic properties make them promising for applications like catalysis. Metallenes stand out due to their abundance of under-coordinated metal atoms, enhancing the catalytic potential by improving atomic utilization and intrinsic activity. This review explores the utility of 2D metals as electrocatalysts in sustainable energy conversion, focusing on the Oxygen Evolution Reaction, Oxygen Reduction Reaction, Fuel Oxidation Reaction, and Carbon Dioxide Reduction Reaction. Aimed at researchers in nanomaterials and energy, the review is a comprehensive resource for unlocking the potential of 2D metals in creating a sustainable energy landscape.

One-pot synthesis of 3D surface-wrinkled PdAu nanospheres for robust alcohols electrocatalysis

Three dimensional (3D) noble-metal nanomaterials with special surface structures have been regarded as high-performance catalysts for alcohol oxidation on account of their superior thermal stability, electrical conductivity and large specific surface area. Although extensive efforts have been devoted to the preparation of 3D Pd-based catalysts with superior activity and stability, designing a simple, effective and eco-friendly method remains a challenge. Herein, we developed a facile one-step coreduction strategy to synthesize a series of 3D surface-wrinkled PdAu nanospheres (NSs) with tunable Pd/Au atomic ratios and found a universal method to prepare surface-wrinkled PdM (M = Au, Pt, Cu and Pb) NSs. Benefiting from the function of the surfactant cetyltrimethylammonium chloride (CTAC), the synthesized PdAu NSs with different composition possess abundant surface wrinkles, which is beneficial for exposing more electroactive centers. Attributed to the unique geometric morphology and optimized atomic ratio, the PdAu-2 NSs exhibited an optimal mass activity (MA) of 8103 mA mg-1 and 5113 mA mg-1 for the ethylene glycol oxidation reaction (EGOR) and ethanol oxidation reaction (EOR), which was 6.1 and 4.1 times that of commercial Pd/C, respectively. Moreover, the PdAu-2 NSs exhibited superb stability after long-term current-time (i-t) and cyclic voltammetry (CV) tests of the EGOR and EOR. This work not only provides new avenues to engineer PdAu NSs with enhanced electrocatalytic performance but also offers guidance for extending to more 3D PdM (M = other metals) NSs with novel morphology applied to fuel cell fields.

Confinement Effects in Carbonized ZIF-Confined Hollow PtCo Nanospheres Enable the Methanol Oxidation Reaction

Confinement effects in highly porous nanostructures can effectively adjust the selectivity and kinetics of electrochemical reactions, which can boost the methanol oxidation reaction (MOR). In this work, carbonized ZIF-8-confined hollow PtCo nanospheres (PtCo@carbonized ZIF-8) were fabricated using a facile strategy. A monodisperse confined region was successfully prepared, and the dispersion of the PtCo nanoparticles (NPs) could be precisely regulated, allowing for the effective tuning of the confined region. Thus, the precise regulation of the catalytic reaction was achieved. Importantly, hollow PtCo NPs were prepared using a method based on the Kirkendall effect, and their forming mechanism was systematically investigated. Because of the confinement effects of carbonized zeolitic imidazolate framework-8 (ZIF-8), the crystal and electronic structures of the PtCo NPs were able to be effectively tuned. Our electrochemical results show that PtCo@carbonized ZIF-8 composites manifest a higher mass activity (1.4 A mgPt-1) and better stability compared to commercial Pt/C.

Interfacial Engineering of Porous Pd/M (M = Au, Cu, Mn) Sponge-like Nanocrystals with a Clean Surface for Enhanced Alkaline Electrochemical Oxidation of Ethanol

The interfacial engineering of Pd-based alloys (i.e., PdM with distinct morphologies, compositions, and strain defects) is an efficient way for enhanced catalytic activity; however, it remains a grand challenge to fabricate such alloys in aqueous solutions without heating, organic solvents, and multiple reaction steps. Herein, we present a simple, aqueous-phase, one-step, and ultrafast approach for the interfacial engineering of surfactant-free porous PdM (M = Cu, Au, and Mn) nanocrystals with well-controlled spongy-like morphology and compositions. The electronic interaction in PdM nanocrystals and their effect on the alkaline electrochemical ethanol oxidation reaction (EOR) are investigated using XRD, XPS, and electrochemical tests. Notably, integrating M metals into Pd atoms results in upshifting the d-band center of Pd and subsequently modulating the EOR activity and stability substantially. The EOR mass activity (10.78 A/mgPd (6.93 A/mgPdCu)) of PdCu was 1.83, 3.09, 4.51, and 53.90 times higher than those of AuPd (5.90 A/mgPd (3.27 A/mgAuPd)), PdMn (3.48 A/mgPd (3.19 A/mgPdMn)), Pd (2.39 A/mgPd), and Pd/C (0.20 A/mgPd), respectively, besides substantial durability after 1000 cycles. This is due to the porous two-dimensional morphology, a low synergetic effect, higher interfacial interaction, and greater active surface area of PdCu, besides a high Cu content with more oxophilicity that facilitates activation/dissociation of H2O to generate -OH species needed for quick EOR electrocatalysis. The electrochemical impedance spectroscopy (EIS) reveals better electrolyte/electrode interfacial interaction and lower charge transfer resistance on PdCu. The EOR activity of PdCu porous sponge-like nanocrystals was superior to all previously reported Pd-based alloys for electrochemical EOR. This study indicates that binary Pd-based catalysts with less synergetic effect are preferred for boosting the EOR activity, which could help in manipulating the surface properties of Pd-based alloys to optimize EOR performance.

Ag Nanoparticle and Ti-MOF Cooperativity for Efficient Inactivation of E. coli in Water

Because of the limitations of traditional chlorine-based bactericidal water treatment, such as the formation of disinfection byproducts (DBPs) and resistance to chlorine, novel approaches and materials are required for effective disinfection of water. This study focuses on the development of a new sterilization material, Ag/NH2-MIL-125(Ti), which was designed to effectively inactivate Escherichia coli in water. The effectiveness of the as-designed material stems from the synergistic interactions between Ag nanoparticles (NPs) and photoactive metal-organic frameworks (MOFs). In this complex material, the MOFs play a critical role in dispersing and isolating the Ag NPs, thus preventing undesirable aggregation during bacterial inactivation. Simultaneously, Ag NPs enhance the photocatalytic performance of the MOFs. Sterilization experiments demonstrate the remarkable rapid E. coli inactivation performance of Ag/NH2-MIL-125(Ti) under illuminated and nonilluminated conditions. Within 25 min of visible light exposure, the as-prepared material achieves a >7-log E. coli reduction. In addition, Ag/NH2-MIL-125(Ti) efficiently decomposes acetic acid, which is the main DBP precursor, under visible light irradiation. Mechanistic investigations revealed that •O2- and h+ were the primary active substances responsible for the inactivation of E. coli and the decomposition of acetic acid, respectively.

Coupling Glycerol Conversion with Hydrogen Production Using Alloyed Electrocatalysts

Herein, uniform precious alloys including PtAg, PdAg, and PtPdAg nanoparticles were synthesized as electrocatalysts for glycerol oxidation reaction (GOR). The structures of the samples were characterized by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectrometry. The catalytic performance of the samples was evaluated in both alkaline and acidic electrolytes. Among the samples, PtPdAg exhibited superior activity with the largest current density of 3.77 mA cm-2 in alkaline solutions, which is 4.1 and 7.7 times those of Pd/C and Pt/C, respectively. In acidic solutions, the PtPdAg catalyst shows the highest current density of 0.58 mA cm-2, which is 1.8 times that of the Pt/C catalyst. The products of GOR were analyzed by high-performance liquid chromatography. Eight products including oxalic acid, tartronic acid, glyoxylic acid, glyceric acid, glyceraldehyde (GLAD), glycolic acid, lactic acid, and dihydroxyacetone were detected. Notably, in acidic solutions, PtAg and PtPdAg yielded the largest GLAD selectivity of 92.2% at 0.6 and 0.8 V, respectively. Using the alloyed catalysts, electrolysis processes coupling the GOR with the hydrogen evolution reaction were conducted. The conversion of glycerol and production of hydrogen were determined. To highlight the energy efficiency, a solar-panel-powered electrolysis process was conducted for the simultaneous production of hydrogen and high-valued products.

DNA-Templated Ag@Pd Nanoclusters for NIR-II Photoacoustic Imaging-Guided Photothermal-Augmented Nanocatalytic Therapy

Developing multifunctional nanozymes with photothermal-augmented enzyme-like reaction dynamics in the second near-infrared (NIR-II) biowindow is of significance for nanocatalytic therapy (NCT). Herein, DNA-templated Ag@Pd alloy nanoclusters (DNA-Ag@Pd NCs) are prepared as a kind of novel noble-metal alloy nanozymes by using cytosine-rich hairpin-shaped DNA structures as growth templates. DNA-Ag@Pd NCs exhibit high photothermal conversion efficiency (59.32%) under 1270 nm laser and photothermally augmented peroxidase-mimicking activity with synergetic enhancement between Ag and Pd. In addition, hairpin-shaped DNA structures on the surface of DNA-Ag@Pd NCs endow them with good stability and biocompatibility in vitro and in vivo, and enhanced permeability and retention effect at tumor sites. Upon intravenous injection, DNA-Ag@Pd NCs demonstrate high-contrast NIR-II photoacoustic imaging-guided efficient photothermal-augmented NCT of gastric cancer. This work provides a strategy to synthesize versatile noble-metal alloy nanozymes in a bioinspired way for highly efficient therapy of tumors.

Programmable Synthesis of High-Entropy Nanoalloys for Efficient Ethanol Oxidation Reaction

Controllable synthesis of nanoscale high-entropy alloys (HEAs) with specific morphologies and tunable compositions is crucial for exploring advanced catalysts. The present strategies either have great difficulties to tailor the morphology of nanoscale HEAs or suffer from narrow elemental distributions and insufficient generality. To overcome the limitations of these strategies, here we report a robust template-directed synthesis to programmatically fabricate nanoscale HEAs with controllable compositions and structures via independently controlling the morphology and composition of HEA. As a proof of concept, 12 kinds of nanoscale HEAs with controllable morphologies of zero-dimension (0D) nanoparticles, 1D nanowires, 2D ultrathin nanorings (UNRs), 3D nanodendrites, and vast elemental compositions combining five or more of Pd/Pt/Ag/Cu/Fe/Co/Ni/Pb/Bi/Sn/Sb/Ge are synthesized. Moreover, the as-prepared HEA-PdPtCuPbBiUNRs/C demonstrates the state-of-the-art electrocatalytic performance for the ethanol oxidation reaction, with 25.6- and 16.3-fold improvements in mass activity, relative to commercial Pd/C and Pt/C catalysts, respectively, as well as greatly enhanced durability. This work provides a myriad of nanoscale HEAs and a general synthetic strategy, which are expected to have broad impacts for the fields of catalysis, sensing, biomedicine, and even beyond.

Hydrogen Permeability of Composite Pd-Au/Pd-Cu Membranes and Methods for Their Preparation

Thin Pd-40%Cu films were obtained via the classical melting and rolling method, magnetron sputtering, and modified with nanostructured functional coatings to intensify the process of hydrogen transportation. The films were modified by electrodeposition, according to the classical method of obtaining palladium black and "Pd-Au nanoflowers" with spherical and pentagonal particles, respectively. The experiment results demonstrated the highest catalytic activity (89.47 mA cm^-2), good resistance to CO poisoning and long-term stability of Pd-40%Cu films with a pentagonal structured coating. The investigation of the developed membranes in the hydrogen transport processes in the temperature range of 25-300 °C also demonstrated high and stable fluxes of up to 475.28 mmol s^-1 m^-2 (deposited membranes) and 59.41 mmol s^-1 m^-2 (dense metal membranes), which were up to 1.5 higher, compared with membrane materials with classic niello. For all-metal modified membranes, the increase in flux was up to sevenfold, compared with a smooth membrane made of pure palladium, and for deposited films, this difference was manyfold. The membrane materials' selectivity was also high, up to 4419. The developed strategy for modifying membrane materials with functional coatings of a fundamentally new complex geometry can shed new light on the development and fabrication of durable and highly selective palladium-based membranes for gas steam reformers.

Nanoarchitectonics of Metallene Materials for Electrocatalysis

Controlling the synthesis of metal nanostructures is one approach for catalyst engineering and performance optimization in electrocatalysis. As an emerging class of unconventional electrocatalysts, two-dimensional (2D) metallene electrocatalysts with ultrathin sheet-like morphology have gained ever-growing attention and exhibited superior performance in electrocatalysis owing to their distinctive properties originating from structural anisotropy, rich surface chemistry, and efficient mass diffusion capability. Many significant advances in synthetic methods and electrocatalytic applications for 2D metallenes have been obtained in recent years. Therefore, an in-depth review summarizing the progress in developing 2D metallenes for electrochemical applications is highly needed. Unlike most reported reviews on the 2D metallenes, this review starts by introducing the preparation of 2D metallenes based on the classification of the metals (e.g., noble metals, and non-noble metals) instead of synthetic methods. Some typical strategies for preparing each kind of metal are enumerated in detail. Then, the utilization of 2D metallenes in electrocatalytic applications, especially in the electrocatalytic conversion reactions, including the hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, fuel oxidation reaction, CO₂ reduction reaction, and N₂ reduction reaction, are comprehensively discussed. Finally, current challenges and opportunities for future research on metallenes in electrochemical energy conversion are proposed.

Towards a scalable and controllable preparation of highly-uniform surface-enhanced Raman scattering substrates: Defect-free nanofilms as templates

The uniformity and reproducibility of substrates highly determine the applicability of surface-enhanced Raman scattering (SERS). Production of them, however, remains a challenge. Herein, we report a template-based strategy for the strictly controllable and handily scalable preparation of a very uniform SERS substrate, Ag nanoparticles (AgNPs)/nanofilm, where the template used is a flexible, transparent, self-standing, defect-free and robust nanofilm. Importantly, the obtained AgNPs/nanofilm is self-adhesive to surfaces of different properties and morphologies, ensuring in-situ and at real-time SERS detection. The enhancement factor (EF) of the substrate for rhodamine 6G (R6G) could reach 5.8 × 10¹⁰ with a detection limit (DL) of 1.0 × 10^-15 mol L^-1. Moreover, 500 bending tests and one-month storage showed no observable performance degradation, and up to 50.0 cm² scaled-up preparation depicted negligible effect upon the structure and the sensing performance. The real-life applicability of AgNPs/nanofilm was demonstrated by the sensitive detection of tetramethylthiuram disulfide on cherry tomato and fentanyl in methanol with a routine handheld Raman spectrometer. This work thus provides a reliable strategy for large area wet-chemical preparation of high-quality SERS substrates.

One-pot synthesis of ultrafine trimetallic PtPdCu alloy nanoparticles decorated on carbon nanotubes for bifunctional catalysis of ethanol oxidation and oxygen reduction

Bifunctional catalysts for ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR) with high noble-metal utilization are highly beneficial to direct ethanol fuel cells (DEFCs). This study developed a ternary bifunctional catalyst composed of ultrafine PtPdCu alloy nanoparticles and carbon nanotubes (CNTs) support through a facile surfactant-free solvothermal route. The carboxyl terminal groups on CNTs ensure the confined growth of PtPdCu alloys (∼5 nm) and suppress Ostwald ripening of metallic active sites during electrochemical cycling. Consequently, PtPdCu/CNTs exhibits high mass activity (1.95 A mg^-1) and specific activity (4.08 mA cm^-2) toward EOR, which are 7.8 and 8.9 times higher, respectively, than those of commercial Pt/C. Furthermore, PtPdCu/CNTs displays superior stability toward EOR compared with its bimetallic counterparts (PtPd/CNTs and PtCu/CNTs). In addition, PtPdCu/CNTs exhibits the highest half-wave potential of 0.888 V among all electrocatalysts, indicating high ORR activity. Density functional theory calculations reveal that Pd and Cu mediate the electronic structure of Pt, leading to enhanced catalytic activity of PtPdCu/CNTs. The excellent catalytic property of PtPdCu/CNTs can also be attributed to the bifunctional effects of Pd/Cu and the interaction between metal and the carbon support. The proposed material is a contribution to the family of efficient ternary-alloy electrocatalysts for fuel cells.

Noble metal nanodendrites: growth mechanisms, synthesis strategies and applications

Inorganic nanodendrites (NDs) have become a kind of advanced nanomaterials with broad application prospects because of their unique branched architecture. The structural characteristics of nanodendrites include highly branched morphology, abundant tips/edges and high-index crystal planes, and a high atomic utilization rate, which give them great potential for usage in the fields of electrocatalysis, sensing, and therapeutics. Therefore, the rational design and controlled synthesis of inorganic (especially noble metals) nanodendrites have attracted widespread attention nowadays. The development of synthesis strategies and characterization methodology provides unprecedented opportunities for the preparation of abundant nanodendrites with interesting crystallographic structures, morphologies, and application performances. In this review, we systematically summarize the formation mechanisms of noble metal nanodendrites reported in recent years, with a special focus on surfactant-mediated mechanisms. Some typical examples obtained by innovative synthetic methods are then highlighted and recent advances in the application of noble metal nanodendrites are carefully discussed. Finally, we conclude and present the prospects for the future development of nanodendrites. This review helps to deeply understand the synthesis and application of noble metal nanodendrites and may provide some inspiration to develop novel functional nanomaterials (especially electrocatalysts) with enhanced performance.

2D-CuPd nanozyme overcome tamoxifen resistance in breast cancer by regulating the PI3K/AKT/mTOR pathway

Tamoxifen is the most commonly used treatment for estrogen-receptor (ER) positive breast cancer patients, but its efficacy is severely hampered by resistance. PI3K/AKT/mTOR pathway inhibition was proven to augment the benefit of endocrine therapy and exhibited potential for reversing tamoxifen-induced resistance. However, the vast majority of PI3K inhibitors currently approved for clinical use are unsatisfactory in terms of safety and efficacy. We developed two-dimensional CuPd (2D-CuPd) nanosheets with oxidase and peroxidase nanozyme activities to offer a novel solution to inhibit the activity of the PI3K/AKT/mTOR pathway. 2D-CuPd exhibit superior dual nanozyme activities converting hydrogen peroxide accumulated in drug-resistant cells into more lethal hydroxyl radicals while compensating for the insufficient superoxide anion produced by tamoxifen. The potential clinical utility was further demonstrated in an orthotopically implanted tamoxifen-resistant PDX breast cancer model. Our results reveal a novel nanozyme ROS-mediated protein mechanism for the regulation of the PI3K subunit, illustrate the cellular pathways through which increased p85β protein expression contributes to tamoxifen resistance, and reveal p85β protein as a potential therapeutic target for overcoming tamoxifen resistance. 2D-CuPd is the first reported nanomaterial capable of degrading PI3K subunits, and its high performance combined with further materials engineering may lead to the development of nanozyme-based tumor catalytic therapy.

Pd-Based Metallenes for Fuel Cell Reactions

Pd-based metallenes, atomically thin layers composed primarily of under-coordinated Pd atoms, have emerged as the newest members in the family of two-dimensional (2D) nanomaterials. Moreover, the unique physiochemical properties, high intrinsic activity associated with metallenes coupled with the ease of applying chemical modifications result in great potential in catalyst engineering for fuel cell reactions. Especially in recent years, interest in Pd-based metallenes is growing, as evidenced by surge in available literatures. Herein, we have reviewed the recent findings achieved in Pd-based metallenes in fuel cells by highlighting the technologies available for deriving metallenes and manifesting the modification strategies for designing them to better suit the application demand. Moreover, we also discuss the perspective insights of Pd-based metallenes for fuel cells regarding the surfactant-free synthesis method, strain engineering, constructing high-entropy alloy, and so on.

Bias-Free Solar-Driven Syngas Production: A Fe2 O3 Photoanode Featuring Single-Atom Cobalt Integrated with a Silver-Palladium Cathode

Photoelectrochemical syngas production from aqueous CO₂ is a promising technique for carbon capture and utilization. Herein, we demonstrate the efficient and tunable syngas production by integrating a single-atom cobalt-catalyst-decorated α-Fe₂ O₃ photoanode with a bimetallic Ag/Pd alloy cathode. A record syngas production activity of 81.9 μmol cm^-2  h^-1 (CO/H₂ ratio: ≈1 : 1) was achieved under artificial sunlight (AM 1.5 G) with an excellent durability. Systematic studies reveal that the Co single atoms effectively extract the holes from Fe₂ O₃ photoanodes and serve as active sites for promoting oxygen evolution. Simultaneously, the Pd and Ag atoms in bimetallic cathodes selectively adsorb CO₂ and protons for facilitating CO production. Further incorporation with a photovoltaic, to allow solar light (>600 nm) to be utilized, yields a bias-free CO₂ reduction device with solar-to-CO and solar-to-H₂ conversion efficiencies up to 1.33 and 1.36 %, respectively.

Colloidal Synthesis of Metal Nanocrystals: From Asymmetrical Growth to Symmetry Breaking

Nanocrystals offer a unique platform for tailoring the physicochemical properties of solid materials to enhance their performances in various applications. While most work on controlling their shapes revolves around symmetrical growth, the introduction of asymmetrical growth and thus symmetry breaking has also emerged as a powerful route to enrich metal nanocrystals with new shapes and complex morphologies as well as unprecedented properties and functionalities. The success of this route critically relies on our ability to lift the confinement on symmetry by the underlying unit cell of the crystal structure and/or the initial seed in a systematic manner. This Review aims to provide an account of recent progress in understanding and controlling asymmetrical growth and symmetry breaking in a colloidal synthesis of noble-metal nanocrystals. With a touch on both the nucleation and growth steps, we discuss a number of methods capable of generating seeds with diverse symmetry while achieving asymmetrical growth for mono-, bi-, and multimetallic systems. We then showcase a variety of symmetry-broken nanocrystals that have been reported, together with insights into their growth mechanisms. We also highlight their properties and applications and conclude with perspectives on future directions in developing this class of nanomaterials. It is hoped that the concepts and existing challenges outlined in this Review will drive further research into understanding and controlling the symmetry breaking process.

One-Pot Au@Pd Dendritic Nanoparticles as Electrocatalysts with Ethanol Oxidation Reaction

The one-pot synthesis strategy of Au@Pd dendrites nanoparticles (Au@Pd DNPs) was simply synthesized in a high-temperature aqueous solution condition where cetyltrimethylammonium chloride (CTAC) acted as a reducing and capping agent at a high temperature. The Au@Pd DNPs with highly monodisperse were shown in high yields by the Au:Pd rate. The nanostructure and optical and crystalline properties of the Au@Pd DNPs were characterized by UV–vis spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction. The Au@Pd DNPs showed an efficient electrochemical catalytic performance rate toward the ethanol oxidation reaction (EOR) due to their nanostructures and Au:Pd rate.

Precisely modulated 2D PdCu alloy nanodendrites as highly active peroxidase mimics for the elimination of biofilms

Pd-based nanomaterials are good candidates for antibacterial applications because of their high catalytic activity and good biocompatibility. Nonetheless, there is still much work to do to improve the catalytic activity of Pd nanomaterials as antibacterial agents, particularly for anti-biofilms. In this work, Cu was introduced into Pd to form a series of 2D PdCu alloy nanodendrites (PdCu NDs) as high-performance peroxidase mimics based on flexible control of compositions. Remarkably, catalytic kinetics show that the composition-dependent synergy in the PdCu NDs strongly enhances the peroxidase-like activity. The detailed theoretical study reveals that the tuning of the electrostatic adsorption and dissociative chemisorption of the H₂O₂ molecule on PdCu ND surfaces by the precise introduction of Cu plays a key role in obtaining superior peroxidase-like catalytic activity. Significantly, the distinct peroxidase-like properties of the fine-tuned PdCu NDs endow them with excellent biofilm elimination capability via the generation of hydroxyl radicals. This work offers a great opportunity to design noble metal nanozymes with enhanced performance, which might advance the development of nanozymes as a new class of highly efficient antibacterial agents.

Toward High-Energy-Density Aqueous Lithium-Ion Batteries Using Silver Nanowires as Current Collectors

The lack of suitable lightweight current collectors is one of the primary obstacles preventing the energy density of aqueous lithium-ion batteries (ALIBs) from becoming competitive. Using silver nanowire (AgNW) films as current collectors and a molecular crowding electrolyte, we herein report the fabrication of ALIBs with relatively good energy densities. In the 2 m LiTFSI-94% PEG-6% H₂O solution, the AgNW films with a sheet resistance of less than 1.0 ohm/square exhibited an electrochemical stability window as broad as 3.8 V. The LiMn₂O₄//Li₄Ti₅O₁₂ ALIBs using AgNW films as the current collectors demonstrated an initial energy density of 70 Wh/kg weighed by the total mass of the cathode and anode, which retained 89.1% after 50 cycles.