Free-Standing Pt–Au Hollow Nanourchins with Enhanced Activity and Stability for Catalytic Methanol Oxidation

Construction of H-Doped PdB Nanocrystals as Electrocatalysts to Modulate Formic Acid Oxidation

The strong ligand effect in B-doped Pd-based (PdB) catalysts renders them a promising anode for constructing formic acid fuel cells (FAFCs) exhibiting high power density and outstanding stability. However, the enhancement of the oxidation barrier is unavoidable in this alloy system owing to the electron transfer (ET) from B to Pd. In this study, a hydrogen doping strategy is employed to open charge freedom in PdB compounds and boost their formic acid oxidation reaction (FAOR) activity by suppressing the ET process. The resulting hydrogen-doped PdB (PdBH) exhibits an ultrahigh mass activity of up to 1.2A mg-1 Pd, which is 3.23 times that of the PdB catalyst and 9.55 times that of Pd black. Detailed experimental and theoretical studies show that the interstitial hydrogen leads to enhanced orbital hybridization and reduced electron density around Pd. This optimized ligand effect weakens the carbon monoxide adsorption and increases the direct pathway preference of PdBH, resulting in its outstanding catalytic activity for the FAOR. The development of this high-performance hydrogen-doped PdB catalyst is an important step toward the construction of advanced light element co-doped metal catalysts.

Unveiling the Dynamic Electrocatalytic Activity of Online Synthesized Bimetallic Nanocatalysts via Electrochemiluminescence Microscopy

Effective bimetallic nanoelectrocatalysis demands precise control of composition, structure, and understanding catalytic mechanisms. To address these challenges, we employ a two-in-one approach, integrating online synthesis with real-time imaging of bimetallic Au@Metal core-shell nanoparticles (Au@M NPs) via electrochemiluminescence microscopy (ECLM). Within 120 s, online electrodeposition and in situ catalytic activity screening alternate. ECLM captures transient faradaic processes during potential switches, visualizes electrochemical processes in real-time, and tracks catalytic activity dynamics at the single-particle level. Analysis using ECL photon flux density eliminates size effects and yields quantitative electrocatalytic activity results. Notably, a nonlinear activity trend corresponding to the shell metal to Au surface atomic ratio is discerned, quantifying the optimal surface component ratio of Au@M NPs. This approach offers a comprehensive understanding of catalytic behavior during the deposition process with high spatiotemporal resolution, which is crucial for tailoring efficient bimetallic nanocatalysts for diverse applications.

Surfactant-free Synthesis of Spiky Hollow Ag-Au Nanostars with Chemically Exposed Surfaces for Enhanced Catalysis and Single-Particle SERS

Spiky/hollow metal nanoparticles have applications across a broad range of fields. However, the current bottom-up methods for producing spiky/hollow metal nanoparticles rely heavily on the use of strongly adsorbing surfactant molecules, which is undesirable because these passivate the product particles' surfaces. Here we report a high-yield surfactant-free synthesis of spiky hollow Au-Ag nanostars (SHAANs). Each SHAAN is composed of >50 spikes attached to a hollow ca. 150 nm diameter cubic core, which makes SHAANs highly plasmonically and catalytically active. Moreover, the surfaces of SHAANs are chemically exposed, which gives them significantly enhanced functionality compared with their surfactant-capped counterparts, as demonstrated in surface-enhanced Raman spectroscopy (SERS) and catalysis. The chemical accessibility of the pristine SHAANs also allows the use of hydroxyethyl cellulose as a weakly bound stabilizing agent. This produces colloidal SHAANs that remain stable for >1 month while retaining the functionalities of the pristine particles and allows even single-particle SERS to be realized.

3D Anisotropic Au@Pt-Pd Hemispherical Nanostructures as Efficient Electrocatalysts for Methanol, Ethanol, and Formic Acid Oxidation Reaction

Anisotropic 3D nanostructures exhibit excellent electrocatalytic activity and stability due to their heterogeneous elemental distribution and unsymmetrical configuration. However, it is still a huge challenge to combine anisotropically distributed elements and anisotropic morphologies within one 3D nanostructure. Herein, 3D Au@Pt-Pd hemispherical nanostructures (Au@Pt-Pd H-Ss) are fabricated as highly efficient electrocatalysts for oxidation reaction, which present heterogenous element distribution and anisotropic morphology. It is demonstrated that the non-uniform adsorption of BO₂ ^- on Au-CTA⁺ surface, as well as the simulated lower formation energy of Pt-Pd atoms for Au-CTA⁺ -BO₂ ^- , basically contribute to the eventual formation of Au@Pt-Pd H-Ss. Impressively, the unique anisotropic Au@Pt-Pd H-Ss exhibit superior electrocatalytic activity and durability for methanol, ethanol, and formic acid oxidation reaction compared with commercial Pt/C and previously reported noble-metal based electrocatalysts. Especially, the mass activity of Au@Pt-Pd H-Ss for MOR is 4.38 A mg_Pt+Pd ^-1 , which is about 2.0 and 4.7 times that of Au@Pt-Pd spherical nanostructures (Au@Pt-Pd Ss) and commercial Pt/C catalyst, respectively. This work provides an important reference for the design and preparation of 3D anisotropic and high-efficiency electrocatalysts.

High-Sensitive MEMS Hydrogen Sulfide Sensor made from PdRh Bimetal Hollow Nanoframe Decorated Metal Oxides and Sensitization Mechanism Study

Here we report the fabrication of a high performance metal oxide semiconductor (MOS) sensor for the detection of hydrogen sulfide (H₂S) using PdRh bimetal hollow nanocube (HC) with Rh-rich hollow frame and Pd-rich core frame as sensitizing materials. PdRh bimetal HC with the edge-length about 10 nm was prepared by chemical etching PdRh bimetal solid nanocube (SC) in HNO₃ aqueous solution. The results of gas-sensing tests indicate that the response value order of the MEMS gas sensors based on MOSs (including ZnO, MoO₃ and SnO₂) is as follows: R_PdRh HC/MOS > R_PdRh SC/MOS > R_MOS. First, in the system of ZnO, gas sensor modified by PdRh (PdRh SC/ZnO and PdRh HC/ZnO) possess enhanced H₂S sensing performance with a better response and excellent low-concentration detection capability (down to 15 ppb) comparing to pure ZnO. The improved H₂S sensing performance could be attributed to the good conductivity of Rh-rich frame, the high catalytic activity of PdRh bimetal and formation of Schottky barrier-type junctions and defect. Second, PdRh HC/ZnO sensor shows better response (185-1 ppm of H₂S) compared to PdRh SC/ZnO sensor (108-1 ppm of H₂S), which is due to the higher specific surface area of PdRh HC/ZnO and good gas diffusion of the hollow structure. This work indicate that the sensitization characteristics of PdRh bimetal HC will provide new paradigms for the future development of the high performance sensor.

Pt Nanoclusters Anchored on Hollow Ag-Au Nanostructures for Electrochemical Oxidation of Methanol

The synthetic method of Pt nanocluster-anchored hollow Ag-Au nanostructures and measurements of their electrocatalytic properties for methanol oxidation reaction (MOR) are reported here. In this synthesis, uniform Ag nanospheres were prepared by reduction of silver nitrate (AgNO3) with sodium borohydride (NaBH4) and then hollow Ag-Au nanostructures were synthesized via galvanic replacement of the as-prepared Ag nanospheres with Au3+. Finally, the reduction of potassium tetrachloroplatinate (II) (K2PtCl4) with ascorbic acid was performed to deposit Pt nanoclusters on the surface of hollow Ag-Au nanostructures. The hollow interior of Pt nanocluster-anchored Ag-Au nanostructures and change in the size of Pt nanoclusters by varying the injected molar ratio of Pt/Au were observed by transmission electron microscopy (TEM). Moreover, other morphological, compositional, and optical information of the obtained nanoscale materials were analyzed by X-ray diffraction analysis (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and ultraviolet-visible spectroscopy (UV-vis). The electrocatalytic ability of the obtained Pt nanocluster-anchored hollow Ag-Au nanostructures toward MOR was confirmed by the results of cyclic voltametric (CV) measurements. The ease of three-step synthetic strategy and good electrocatalytic performance of the Pt nanocluster-anchored hollow Ag-Au nanostructures displayed their promising potential in the use of electrochemical oxidation of methanol.

An electrochemical daunorubicin sensor based on the use of platinum nanoparticles loaded onto a nanocomposite prepared from nitrogen decorated reduced graphene oxide and single-walled carbon nanotubes

A glassy carbon electrode (GCE) was modified with a nanocomposite prepared from nitrogen-doped reduced graphene oxide (N-rGO) and single walled carbon nanotubes (SWCNTs), and then loaded with platinum nanoparticles (Pt NPs) to obtain a voltammetric sensor for daunorubicin (DNR). Reductive doping of GO and the crystallization of the Pt NPs were carried out in a one-step hydrothermal process. The modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry. It exhibited high sensitivity compared with unmodified electrode. Some experimental parameters which affected sensor response were optimized. Under optimum conditions and at a working voltage of typically -0.56 V (vs. Ag/AgCl), the sensor has a low detection limit (3 ng mL^-1), a wide linear range (0.01-6 μg mL^-1) and good long-term stability. The method was successfully applied to the sensitive and rapid determination of DNR in spiked human serum samples. Graphical abstract Platinum nanoparticles were loaded onto a nanocomposite prepared from nitrogen decorated reduced graphene oxide and single-walled carbon nanotubes (N-rGO-SWCNTs-Pt) and then used for electrochemical determination of daunorubicin (DNR).

Digestive ripening mechanism investigation in a classical Lee–Meisel method based on in situ UV-vis spectra

Digestive ripening is introduced into the classical Lee–Meisel synthesis to obtain uniform and size-controllable Ag nanoparticles.

Galvanic replacement mediated 3D porous PtCu nano-frames for enhanced ethylene glycol oxidation

Galvanic replacement mediated 3D porous PtCu nano-frames possessed enhanced electrocatalytic activity and stability during ethylene glycol oxidation.

Standing Mesochannels: Mesoporous PdCu Films with Vertically Aligned Mesochannels from Nonionic Micellar Solutions

Mesoporous bimetallic palladium (Pd) alloy films with mesochannels perpendicularly aligned to the substrate are expected to show superior electrocatalytic activity and stability. The perpendicular mesochannels allow small molecules to efficiently access the active sites located not only at the surface but also within the film because of low diffusion resistance. When compared to pure Pd films, alloying with a secondary metal such as copper (Cu) is cost-effective and promotes resistance against adventitious poisoning through intermediate reactions known to impair the electrocatalytic performance. Here, we report the synthesis of mesoporous PdCu films by electrochemical deposition in nonionic micellar solutions. The mesoporous structures are vertically aligned on the substrate, and the final content of Pd and Cu can be adjusted by tuning the initial precursor molar ratio in the electrolyte solution.

Insight of holey-graphene in the enhancing of electrocatalytic activity as supporting material

An ideal supporting material improves both activity and durability of noble metal nanoparticles in electrocatalytic reactions. Graphene possesses a high transport rate of electrons in-plane, a low cost, and stability, but, the restacking of graphene layers trap noble metal nanoparticles and make them inaccessible to reactants and results in reduced catalytic activity. Here, holey-graphene as the supporting materials for Pt nanoparticle catalysts is deeply investigated in the electrocatalytic reaction of methanol oxidation. The holey-graphene can be scalable to synthesize using our simple method described herein. The holes on the holey-graphene layer promote the access of reactants with Pt nanoparticle catalysts compared with carbon black and graphene when used as supporting materials. Density functional theory calculations and molecule dynamic simulation further explain the function of holey-graphene in the promotion of electrocatalytic activity. Holey-graphene may open extraordinary possibilities as a supporting material for electrocatalysts.

The Modification of Pt/Graphene Composites with Oxophilic Metal Bi (Bi2O3) and Its Dual-Functional Electro-Photo Catalytic Performance

The Pt-Bi (Bi2O3)/GNs (PVP) composite was synthesized using aqueous solution synthesis and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and Raman spectroscopy. It was found that the water-soluble polyvinyl pyrrolidone (PVP) helped to tune the particles’ morphology, resulting in a uniform distribution of Pt-Bi nanoclusters on the surface of graphene. Cyclic voltammetry, chronoamperometry and linear scanning voltammetry (LSV) were used to study the electrocatalytic properties towards a methanol oxidation reaction (MOR) and an oxygen reduction reaction (ORR). The results show that Pt-Bi (Bi2O3)/GNs (PVP) exhibits superior bifunctional electrocatalytic properties for both MOR and ORR, mainly due to the introduction of oxophilic Bi species and the better dispersion of the Pt-Bi nanoclusters. In particular, the electro-photo catalysis for both MOR and ORR occurred under simulated sunlight irradiation due to the existence of photo-responsive Bi species, which is helpful for converting solar energy into electric energy during a traditional electrocatalytic process.

Hollow Echinus-like PdCuCo Alloy for Superior Efficient Catalysis of Ethanol

Large-scale preparation of hollow echinus-like PdCuCo alloy nanostructures (HENSs) with a high surface area-to-volume ratio, rich active sites, and relatively efficient catalytic activity has attracted considerable research interest. Herein, we present an economic and facile approach to synthesize HENSs by galvanic exchange reactions using Co nanospheres as sacrificial templates. Moreover, the catalytic activity could be adjusted via changing the composition of the catalyst. The composition, morphology, and crystal structure of the as-obtained nanomaterials are characterized by various techniques, such as inductively coupled plasma atomic emission spectrometry, transmission electron microscopy, and X-ray diffraction. Electrochemical catalytic measurement results prove that the Pd₇₅Cu₈Co₃ catalyst obtained under optimal preparation conditions exhibits 10-fold higher activity for ethanol oxidation in comparison with the commercially available 20% Pd/C catalyst. The eminent performance of the Pd₇₅Cu₈Co₃ electrochemical catalyst could be ascribed to the peculiar echinus-like nanostructures.

Designing Novel Nonsymmetric Ag/AgI Nanoplates for Superior Photocatalytic Activity

Precisely engineering the decoration of metal nanoparticles on the special surface of semiconductor represents a promising strategy to design efficient metal-semiconductor heterostructured photocatalysts. This study demonstrates a versatile soft-template method to fabricate a novel nonsymmetrical heterostructured Ag/AgI nanoplate, in which only one side surface of the nanoplate is covered with uniform 2D Ag nanoweb. Compared with symmetrical heterostructure, the nonsymmetrical heterostructure may further facilitate the separation of photogenerated electron-hole pairs and shows a greatly enhanced photocatalytic activity. This study may open up a new way to improve the photocatalytic property by synthesizing nonsymmetrical metal-semiconductor composites.

One-step synthesis of Pt based electrocatalysts encapsulated by polyoxometalate for methanol oxidation

Pt-based electrocatalysts encapsulated by polyoxometalate were synthesized in one step and showed good performance for the methanol oxidation reaction.

One-step synthesis of non-symmetric CuI nanoplates for a highly sensitive non-enzymatic glucose biosensor

A novel non-symmetric CuI nanoplate with only one side covered with teeth-like tips shows highly enhanced biosensor sensitivity.

Effect of Dimensionality and Doping in Quasi-"One-Dimensional (1-D)" Nitrogen-Doped Graphene Nanoribbons on the Oxygen Reduction Reaction

Designing an efficient metal-free electrocatalyst for the oxygen reduction reaction (ORR) is a challenging research theme having enormous practical importance in several renewable energy technologies like fuel cell and metal-air batteries. Here we discuss a cost-effective and commercially viable strategy to develop high-performance nitrogen-doped graphene nanoribbon (N-GNR), which is a quasi-"one-dimensional" analogue of graphene. We have selected the N-GNR system to identify the doping-induced variation in the distribution of active catalytic sites experimentally in graphene-based electrocatalysts. N-GNR exhibits a comparable exchange current density (1.65 × 10^-9 vs 2.25 × 10^-9 A cm^-2), thermodynamic potential (0.80 vs 0.83 V), and smaller Tafel slope (55 vs 60 mV dec^-1) with respect to the benchmarking platinum/carbon (Pt/C), and also, more precisely, it goes through a four-electron pathway with low hydrogen peroxide yield. Although the exact mechanism is still not clear, the theme of the work is based on the identification of the possible active sites with the help of experimental evidence like X-ray photoelectron spectroscopy. These results support the assumption that an edge N (pyridinic N)-bonded adjacent C lowers the activation energy barriers of O₂ adsorption, predominantly to kinetically facilitate the ORR activity. We hope these results will be helpful in developing more efficient ORR catalysts.

Localization of platinum nanoparticles on inner walls of mesoporous hollow carbon spheres for improvement of electrochemical stability

Mesoporous hollow carbon spheres with Pt nanoparticles (NPs) loaded on their inner walls (Pt@HC-meso) have been designed and prepared through a dual-templating method. The core-shell structured Pt/SiO₂@micelle-polydopamine (PDA) precursor is obtained by first depositing Pt NPs on silica spheres and then coating them with the carbon precursor of PDA and diblock copolymer micelles as soft templates. The subsequent carbonization and KOH etching convert the micelle-PDA shells into mesoporous carbon and remove the silica cores, respectively. Thus, the Pt NPs are subjected to calcination and left on the inner walls. The fabricated Pt@HC-meso achieved high electrocatalytic performance and outstanding stability in catalyzing methanol oxidation. We infer that the mesoporous carbon shells not only provide accessible diffusion pathways for the reactants, but also protect the inner Pt NPs from collision with Pt NPs in other hollow carbon spheres. Each hollow carbon sphere with Pt NPs inside can be regarded as an independent nanoreactor. Moreover, observations of the morphology have proved that the calcined Pt NPs avoid a second aggregation during the electrocatalytic process and maintain long-term stability.

M13 Virus-Incorporated Biotemplates on Electrode Surfaces To Nucleate Metal Nanostructures by Electrodeposition

We report a virus-incorporated biological template (biotemplate) on electrode surfaces and its use in electrochemical nucleation of metal nanocomposites as an electrocatalytic material for energy applications. The biotemplate was developed with M13 virus (M13) incorporated in a silicate sol-gel matrix as a scaffold to nucleate Au-Pt alloy nanostructures by electrodeposition, together with reduced graphene oxide (rGO). The phage when engineered with Y3E peptides could nucleate Au-Pt alloy nanostructures, which ensured adequate packing density, simultaneous stabilization of rGO, and a significantly increased electrochemically active surface area. Investigation of the electrocatalytic activity of the resulting sol-gel composite catalyst toward methanol oxidation in an alkaline medium showed that this catalyst had mass activity greater than that of the biotemplate containing wild-type M13 and that of monometallic Pt and other Au-Pt nanostructures with different compositions and supports. M13 in the nanocomposite materials provided a close contact between the Au-Pt alloy nanostructures and rGO. In addition, it facilitated the availability of an OH^--rich environment to the catalyst. As a result, efficient electron transfer and a synergistic catalytic effect of the Au and Pt in the alloy nanostructures toward methanol oxidation were observed. Our nanocomposite synthesis on the novel biotemplate and its application might be useful for developing novel clean and green energy-generating and energy-storage materials.

A self-supporting bimetallic Au@Pt core-shell nanoparticle electrocatalyst for the synergistic enhancement of methanol oxidation

The morphology of Pt−Au bimetal nanostructures plays an important role in enhancing the catalytic capability, catalytic stability and utilization efficiency of the platinum. We designed and successfully prepared Au@Pt nanoparticles (NPs) through an economical, surfactant-free and efficient method of seed-mediated growth. The Au@Pt NPs displayed electrochemical performances superior to those of commercial Pt/C catalysts because their agglomeration was prevented and exhibited better long-term stability with respect to methanol oxidation in acidic media by efficiently removing intermediates. Among the obtained Au@Pt NPs, Au₉₀@Pt₁₀ NPs exhibited the most significantly enhanced catalytic performance for the methanol oxidation reaction (MOR). Their mass and electrochemically active surface area (ECSA)-normalized current densities are approximately 3.9 and 4.6 times higher than those of commercial Pt/C catalysts, respectively. The oxidation current densities of the Au₉₀@Pt₁₀ NPs are approximately 1.8 times higher than those of commercial Pt/C catalysts after 4000 s of continuous measurement because the small Pt NPs grown on the surface of the Au₉₀@Pt₁₀ NPs were effectively stabilized by the Au metal support. This approach may be a facile method for the synthesis of self-supported bimetallic nanostructures, which is of great significance for the development of high performance electrocatalysts and sensors.

Synergistic Effects in CNTs-PdAu/Pt Trimetallic Nanoparticles with High Electrocatalytic Activity and Stability

We present a straightforward physical approach for synthesizing multiwalled carbon nanotubes (CNTs)-PdAu/Pt trimetallic nanoparticles (NPs), which allows predesign and control of the metal compositional ratio by simply adjusting the sputtering targets and conditions. The small-sized CNTs-PdAu/Pt NPs (~3 nm, Pd/Au/Pt ratio of 3:1:2) act as nanocatalysts for the methanol oxidation reaction (MOR), showing excellent performance with electrocatalytic peak current of 4.4 A mgPt -1 and high stability over 7000 s. The electrocatalytic activity and stability of the PdAu/Pt trimetallic NPs are much superior to those of the corresponding Pd/Pt and Au/Pt bimetallic NPs, as well as a commercial Pt/C catalyst. Systematic investigation of the microscopic, crystalline, and electronic structure of the PdAu/Pt NPs reveals alloying and charge redistribution in the PdAu/Pt NPs, which are responsible for the promotion of the electrocatalytic performance.

Dendrite-like PtAg alloyed nanocrystals: Highly active and durable advanced electrocatalysts for oxygen reduction and ethylene glycol oxidation reactions

In this work, well-defined dendrite-like PtAg alloyed nanocrystals were prepared by a facile one-pot l-hydroxyproline-assisted successive coreduction approach on a large scale, where no any template or seed involved. l-Hydroxyproline was employed as a green structuring director. The formation mechanism of the alloyed dendritic nanocrystals was investigated in details. The as-prepared frameworks exhibited boosted electrocatalytic activity, improved stability and enhanced tolerance toward oxygen reduction reaction (ORR) and ethylene glycol oxidation reaction (EGOR) in alkaline media in contrast with commercial Pt black catalyst. The developed method provides novel strategy for preparing other shape-controlled nanocatalysts with superior catalytic activity and durability.

Self-Supported PtAuP Alloy Nanotube Arrays with Enhanced Activity and Stability for Methanol Electro-Oxidation

Inhibiting CO formation can more directly address the problem of CO poisoning during methanol electro-oxidation. In this study, 1D self-supported porous PtAuP alloy nanotube arrays (ANTAs) are synthesized via a facile electro-codeposition approach and present enhanced activity and improved resistance to CO poisoning through inhibiting CO formation (non-CO pathway) during the methanol oxidation reaction in acidic medium. This well-controlled Pt-/transition metal-/nonmetal ternary nanostructure exhibits a specific electroactivity twice as great as that of PtAu alloy nanotube arrays and Pt/C. At the same time, PtAuP ANTAs show a higher ratio of forward peak current density (I_f ) to backward peak current density (I_b ) (2.34) than PtAu ANTAs (1.27) and Pt/C (0.78). The prominent I_f /I_b value of PtAuP ANTAs indicates that most of the intermediate species are electro-oxidized to carbon dioxide in the forward scan, which highlights the high electroactivity for methanol electro-oxidation.

One-Pot Fabrication of Hollow and Porous Pd-Cu Alloy Nanospheres and Their Remarkably Improved Catalytic Performance for Hexavalent Chromium Reduction

Noble metal nanostructures (NMNSs) play a crucial role in many heterogeneous catalytic reactions. Hollow and porous NMNSs possess generally prominent advantages over their solid counterparts due to their unordinary structural features. In this work, we describe a facial one-pot synthesis of hollow and porous Pd-Cu alloy nanospheres (Pd-Cu HPANSs) through a polyethylenimine (PEI)-assisted oxidation-dissolution mechanism. The strong coordination interaction between Cu^II and PEI facilitates the oxidation-dissolution of the Cu₂O nanospheres template under air conditions, which is responsible for the generation of the Pd-Cu alloy and the convenient removal of the Cu₂O nanospheres template at room temperature. Compared to the commercial Pd black, the Pd-Cu HPANSs show remarkably improved catalytic activity for the reduction of K₂Cr₂O₇ by HCOOH at room temperature, attributing to the enhanced catalytic activity of the Pd-Cu HPANSs for the dehydrogenation decomposition of HCOOH.

Coating Carbon Nanosphere with Patchy Gold for Production of Highly Efficient Photothermal Agent

Gold- or carbon-based photothermal therapy (PTT) agents have shown encouraging therapeutic effects of PTT in the near-infrared region (NIR) in many preclinical animal experiments. It is expected that gold/carbon hybrid nanomaterial will possess combinational NIR light absorption and can achieve further improvement in photothermal conversion efficiency. In this work, we design and construct a novel PTT agent by coating a carbon nanosphere with patchy gold. To synthesize this composite particle with Janus structure, a new versatile approach based on a facile adsorption-reduction method was presented. Different from the conventional fabrication procedures, the formation of patchy gold in this approach is mainly a thermodynamics-driven spontaneous process. The results show that when compared with the conventional PTT agent gold nanorod the obtained nanocomposites not only have higher photothermal conversion efficiency but also perform more thermally stable. On the basis of these outstanding photothermal effects, the in vitro and in vivo photothermal performances in a MCF-7 cells (human breast adenocarcinoma cell line) and mice were investigated separately. Additionally, to further illustrate the advantage of this asymmetric structure, their potential was explored by selective surface functionalization, taking advantage of the affinity of both patchy gold and carbon domain to different functional molecules. These results suggest that this new hybrid nanomaterial can be used as an effective PTT agent for cancer treatment in the future.

Catalytic activities for methanol oxidation on ultrathin CuPt3 wavy nanowires with/without smart polymer

CuPt₃ nanowires are synthesized with a thermosensitive amine-terminated poly(N-isopropylacrylamide) polymer, displaying “smart” temperature-controllable electrocatalytic activity towards the methanol oxidation reaction.

Superior catalytic activity and stability for the methanol oxidation reaction of a direct methanol–air fuel cell is achieved with “clean” ultrathin CuPt₃ wavy nanowires. The nanowires are synthesized for the first time by functionalizing CuPt₃ nanoparticles with amine-terminated poly(N-isopropylacrylamide), a thermosensitive “smart” polymer having a phase transition at a liquid-electrolyte T_t (low critical solution temperature, 35 °C). Interestingly, retention of the functionalizing smart polymer on the surface of the nanowires reversibly switches the catalytic activity to lower rates above the T_t. The catalytic performance of the “clean” CuPt₃ nanowires is shown to be significantly improved over that of commercial Pt black catalyst, owing to their unique structural advantages and bimetallic synergetic effect.

In Situ Growth of Prussian Blue Nanostructures at Reduced Graphene Oxide as a Modified Platinum Electrode for Synergistic Methanol Oxidation

Herein, we report a facile synthetic strategy for the in situ growth of Prussian blue nanostructures (PB NSs) at the amine-functionalized silicate sol-gel matrix (TPDT)-RGO composite via the electrostatic interaction. Subsequently, Pt nanostructures are electrodeposited onto the preformed ITO/TPDT-RGO-PB electrode to prepare the RGO/PB/Pt catalyst. The significance of the present method is that the PB NSs are in situ grown by interconnecting the RGO layers, leading to 3D cage-like porous nanostructure. The modified electrodes are characterized by FESEM, EDAX, XRD, XPS, and electrochemical techniques. The RGO/PB/Pt catalyst exhibits synergistic electrocatalytic activity and high stability toward methanol oxidation. The porous nature of the TPDT and PB and unique electron-transfer mediating behavior of PB integrated with RGO in the presence of Pt nanostructures facilitated synergistic electrocatalytic activity for methanol oxidation.

Highly Active Nanoreactors: Patchlike or Thick Ni Coating on Pt Nanoparticles Based on Confined Catalysis

Catalyst-containing nanoreactors have attracted considerable attention for specific applications. Here, we initially report preparation of PtNi@SiO2 hollow microspheres based on confined catalysis. The previous encapsulation of dispersed Pt nanoparticles (NPs) in hollow silica microspheres ensures the formation of Pt@Ni coreshell NPs inside the silica porous shell. Thus, the Pt NPs not only catalyze the reduction of Ni ions but also direct Ni deposition on the Pt cores to obtain Pt@Ni core-shell catalyst. It is worthy to point out that this synthetic approach helps to form a patchlike or thick Ni coating on Pt cores by controlling the penetration time of Ni ions from the bulk solution into the SiO2 microspheres (0.5, 1, 2, or 4 h). Notably, the Pt@Ni core-shell NPs with a patch-like Ni layer on Pt cores (0.5 and 1 h) show a higher H2 generation rate of 1221-1475 H2 mL min(-1) g(-1)cat than the Pt@Ni NPs with a thick Ni layer (2 and 4 h, 920-1183 H2 mL min(-1) g(-1)cat), and much higher than that of pure Pt NPs (224 H2 mL min(-1) g(-1)cat). In addition, the catalyst possesses good stability and recyclability for H2 generation. The Pt@Ni core-shell NPs confined inside silica nanocapsules, with well-defined compositions and morphologies, high H2 generation rate, and recyclability, should be an ideal catalyst for specific applications in liquid phase reaction.

Facile synthesis of gold–platinum dendritic nanostructures with enhanced electrocatalytic performance for the methanol oxidation reaction

Gold–platinum dendritic nanoparticles prepared through a surfactant-free wet-chemical route exhibited good catalytic performance for the methanol oxidation reaction.

The facile ionic liquid-assisted synthesis of hollow and porous platinum nanotubes with enhanced catalytic performances

A facile one-pot synthetic method was developed to synthesize hollow and porous Pt nanotubes (Pt-HPNTs) using silica nanorods as a template, ionic liquid as a precipitator and reductant, and in situ generated KCl as an etching agent.

Tailoring the structure and electronic properties of platinum and gold–platinum nanocatalysts towards enhanced O2 activation

The structural designing of a precious metal molecular catalyst by doping is proved to significantly enhance its activity.

Ultrafine Pt nanoparticle decoration with CoP as highly active electrocatalyst for alcohol oxidation

Ultrafine Pt nanoparticles decorated with CoP provide a promising bifunctional electrocatalyst for alcohol oxidation.

Key parameters governing metallic nanoparticle electrocatalysis

Engineering metallic nanoparticles constitutes a powerful route to design next-generation electrocatalysts to be used in future energy and environmental industries. In this mini review, we cover recent advances in metallic nanoparticle electrocatalysis, with a focus on understanding how the parameters such as particle sizes, crystalline structures, shapes, compositions, nanoscale alloying and interfaces influence their electrocatalytic activity and selectivity. In addition, this review highlights viable approaches for fabrication of nanoparticle-based electrocatalytic electrodes and discusses their influences on the overall catalytic performances. Finally, we discuss the opportunities and challenges ahead to program these key parameters to achieve highly durable designer electrocatalysts in future.

Heterostructured Au/Pd-M (M = Au, Pd, Pt) nanoparticles with compartmentalized composition, morphology, and electrocatalytic activity

The synthesis, processing, and galvanic exchange of three heterostructured nanoparticle systems is described. The surface accessibility and redox potential of a Au/Pd-Ag dumbbell nanoparticle, where a Au/Pd core/shell region, and a silver region make up the domains, was used to prepare the new nanostructures with controlled composition, morphology, and microstructure. Results indicate that the silver domain was particularly susceptible to galvanic displacement, and was exchanged to Au/Pd-M (M = Au, Pd, Pt). Interestingly, the dumbbell morphology remained after exchange, and the silver region was transformed to hollow, parachute, or concentric domains respectively. The morphology and microstructure change was visualized via TEM and HRTEM, and the composition changes were probed via STEM-EDS imaging and XPS. The electrocatalytic activity of the Au/Pd-M towards methanol oxidation was studied, with results indicating that the Au/Pd-Pt nanoparticles had high activity attributed to the porous nature of the platinum domains.