Hierarchical Spatial Confinement Unlocking the Storage Limit of MoS2 for Flexible High-Energy Supercapacitors

Molybdenum sulfide (MoS2) is a promising electrode material for supercapacitors; however, its limited Mo/S edge sites and intrinsic inert basal plane give rise to sluggish active electronic states, thus constraining its electrochemical performance. Here we propose a hierarchical confinement strategy to develop ethylene molecule (EG)-intercalated Co-doped sulfur-deficient MoS2 (Co-EG/SV-MoS2) for efficient and durable K-ion storage. Theoretical analyses suggest that the intercalation-confined EG and lattice-confined Co can enhance the interfacial K-ion storage capacity while reducing the K-ion diffusion barrier. Experimentally, the intercalated EG molecules with mildly reducing properties induced the creation of sulfur vacancies, expanded the interlayer spacing, regulated the 2H-1T phase transition, and strengthened the structural grafting between layers, thereby facilitating ion diffusion and ensuring structural durability. Moreover, the Co dopants occupying the initial Mo sites initiated charge transfer, thus activating the basal plane. Consequently, the optimized Co-EG/SV-MoS2 electrode exhibited a substantially improved electrochemical performance. Flexible supercapacitors assembled with Co-EG/SV-MoS2 delivered a notable areal energy density of 0.51 mW h cm-2 at 0.84 mW cm-2 with good flexibility. Furthermore, supercapacitor devices were integrated with a strain sensor to create a self-powered system capable of real-time detection of human joint motion.

Synthesis of millimeter-scale ZIF-8 single crystals and their reversible crystal structure changes

Among various metal-organic frameworks (MOFs), the zeolitic imidazole framework (ZIF), constructed by the regular arrangement of 2-methylimidazole and metal ions, has garnered significant attention due to its distinctive crystals and pore structures. Variations in the sizes and shapes of ZIF crystals have been reported by changing the synthesis parameters, such as the molar ratios of organic ligands to metal ions, choice of solvents, and temperatures. Nonetheless, the giant ZIF-8 single crystals beyond the typical range have rarely been reported. Herein, we present the synthesis of millimeter-scale single crystal ZIF-8 using the solvothermal method in N,N-diethylformamide. The resulting 1-mm single crystal is carefully characterized through N2 adsorption-desorption isotherms, scanning electron microscopy, and other analytical techniques. Additionally, single-crystal X-ray diffraction is employed to comprehensively investigate the framework's mobility at various temperatures.

Excess heat production of the pair annihilation of ionic vacancies in a copper redox reaction using a double bipolar MHD electrode

Through a copper double bipolar magnetohydrodynamic (MHD) electrode (MHDE) producing twice the amounts of ionic vacancies than a conventional single MHDE, the molar excess heat of the pair annihilation of ionic vacancies, 702 kJ mol-1 at 10 T on average was obtained in a copper redox reaction. It was about twice as large as that of a single MHDE, 387 kJ mol-1 at the same magnetic field. This result strongly suggests that a multi-channel bipolar MHDE will produce much greater excess heat. To conserve the linear momentum and electric charge during electron transfer in an electrode reaction, ionic vacancies are created, storing the solvation energy in the polarized core of the order of 0.1 nm, and the pair annihilation of the vacancies with opposite charges liberates the energy as excess heat. The promoted excess heat by the double bipolar MHDE with a diffuser at 10 T was 710 ± 144 kJ mol-1, whereas as mentioned above, 702 ± 426 kJ mol-1 was obtained by the same electrode without such a diffuser. From the theoretical excess heat of 1140 kJ mol-1, the collision efficiencies in pair annihilation were 0.623 ± 0.126 and 0.616 ± 0.374, respectively. From these results, the reproducibility of the thermal measurement was experimentally validated. At the same time, it was concluded that at magnetic fields beyond 10 T, the concentration of ionic vacancy and the collision efficiency take constant uppermost values.

Enhancing Electrocatalytic Performance via Thickness-Tuned Hollow N-Doped Mesoporous Carbon with Embedded Co Nanoparticles for Oxygen Reduction Reaction

Improving catalytic performance relies heavily on the rational design of the spatial structure of electrocatalysts, achieved through exposure of active sites, acceleration of the charge/mass transfer rate, and confinement of the reactants. In this study, we have fabricated Co nanoparticles embedded in overhang eave-like hollow N-doped mesoporous carbon (Co@EMPC) by adjusting the thickness of mesoporous polydopamine (mPDA). Thanks to the abundance of short mesoporous channels within the porous structure and the tuned electronic properties resulting from heterojunction structures between metal and carbon, the prepared Co@EMPC provides increased accessibility to active sites and enhanced mass and charge transfer rates. These features contribute to superior performance in the oxygen reduction reaction (ORR), with a half-wave potential of 0.874 V vs RHE, as well as exceptional durability in alkaline media. This study introduces a useful approach to enhance the ORR using eave-like hollow nanoreactors.

Anisotropic Interface Successive Assembly for Bowl-Shaped Metal-Organic Framework Nanoreactors with Precisely Controllable Meso-/Microporous Nanodomains

Colloidal metal-organic framework (MOF) nanoparticles, with tailored asymmetric nanoarchitectures and hierarchical meso-/microporosities, have significant implications in high-performance nanocatalysts, nanoencapsulation carriers, and intricate assembly architectures. However, the methodology that could achieve precise control over the anisotropic growth of asymmetric MOF particles with tailored distributions of meso- and microporous regions has not yet been established. In this study, we introduce a facile anisotropic interface successive assembly approach to synthesize asymmetric core-shell MOF (ZIF-67) nanobowls with worm-like mesopores in the core and intrinsic micropores in the shell. Our synthesis pathway relies on anisotropic nucleation of mesoporous MOF nanohemispheres on emulsion interfaces through the cooperative assembly of surfactants and MOF precursors. This is followed by the growth of microporous MOF layers on both interfaces of mesoporous cores and emulsion droplets, resulting in a hierarchically porous core-shell nanostructure. By utilizing this multi-interface-driven approach, we enable the creation of diverse geometries and distributions of mesopores and micropores in asymmetric MOF nanoarchitectures. The obtained bowl-like meso-/microporous core-shell ZIF-67 particles exhibit enhanced catalytic activity for CO2 cycloaddition, attributed to reactant accumulation within the bowl-like architecture, active site accessibility in the open mesoporous core, and improved structural stability. Overall, our study provides insights and inspiration for exploring the intricate asymmetric nanostructures of hierarchically porous MOFs with diverse potential applications.

Selective Etching of Metal-Organic Frameworks for Open Porous Structures: Mass-Efficient Catalysts with Enhanced Oxygen Reduction Reaction for Fuel Cells

Fe-Nx-C-based single-atom (SA-Fe-N-C) catalysts have shown favorable oxygen reduction reaction (ORR) activity. However, their application in proton exchange membrane fuel cells is hindered by reduced performance owing to the thick catalyst layer, restricting mass transfer and the O2 supply. Metal-organic frameworks (MOFs) are a promising class of crystal materials, but their narrow pores exacerbate the sluggish mass-transport properties within the catalyst layer. This study developed an approach for constructing an open-pore structure in MOFs via chelation-assisted selective etching, resulting in atomically dispersed Fe atoms anchored on an N, S co-doped carbon framework. The open-pore structure reduces oxygen transport resistance in the membrane electrode assembly (MEA) with unprecedented ORR activity and stability, as evidenced by finite element simulations. In an acidic electrolyte, the OP-Fe-NC catalyst shows a half-wave potential of 0.89 V vs RHE, surpassing Pt/C by 20 mV, and a current density of 29 mA cm-2 at 0.9 ViR-free in the MEA. This study provides an effective structural strategy for fabricating electrocatalysts with high mass efficiency and atomic precision for energy storage and conversion devices.

Evoking C2+ production from electrochemical CO2 reduction by the steric confinement effect of ordered porous Cu2O

Selective conversion of carbon dioxide (CO2) to multi-carbon products (CO2-to-C2+) at high current densities is in essential demand for the practical application of the resultant valuable products, yet it remains challenging to conduct due to the lack of efficient electrocatalysts. Herein, three-dimensional ordered porous cuprous oxide cuboctahedra (3DOP Cu2O-CO) were designed and synthesized by a molecular fence-assisted hard templating approach. Capitalizing on the merits of interconnected and uniformly distributed pore channels, 3DOP Cu2O-CO exhibited outstanding electrochemical CO2-to-C2+ conversion, achieving faradaic efficiency and partial current density for C2+ products of up to 81.7% and -0.89 A cm-2, respectively, with an optimal formation rate of 2.92 mmol h-1 cm-2 under an applied current density of -1.2 A cm-2. In situ spectroscopy and simulation results demonstrated that the ordered pores of 3DOP Cu2O-CO can effectively confine and accumulate sufficient *CO adsorption during electrochemical CO2 reduction, which facilitates efficient dimerization for the formation of C2+ products. Furthermore, the 3DOP structure induces a higher local pH value, which not only enhances the C-C coupling reaction, but also suppresses competing H2 evolution.

A facile dual-template-directed successive assembly approach to hollow multi-shell mesoporous metal-organic framework particles

Hollow multi-shell mesoporous metal-organic framework (MOF) particles with accessible compartmentalization environments, plentiful heterogeneous interfaces, and abundant framework diversity are expected to hold great potential for catalysis, energy conversion, and biotechnology. However, their synthetic methodology has not yet been established. In this work, a facile dual-template-directed successive assembly approach has been developed for the preparation of monodisperse hollow multi-shell mesoporous MOF (UiO-66-NH2) particles through one-step selective etching of successively grown multi-layer MOFs with alternating two types of mesostructured layers. This strategy enables the preparation of hollow multi-shell mesoporous UiO-66-NH2 nanostructures with controllable shell numbers, accessible mesochannels, large pore volume, tunable shell thickness and chamber sizes. The methodology relies on creating multiple alternating layers of two different mesostructured MOFs via dual-template-directed successive assembly and their difference in framework stability upon chemical etching. Benefiting from the highly accessible Lewis acidic sites and the accumulation of reactants within the multi-compartment architecture, the resultant hollow multi-shell mesoporous UiO-66-NH2 particles exhibit enhanced catalytic activity for CO2 cycloaddition reaction. The dual-template-directed successive assembly strategy paves the way toward the rational construction of elaborate hierarchical MOF nanoarchitectures with specific physical and chemical features for different applications.

Spontaneous generation of singlet oxygen on microemulsion-derived manganese oxides with rich oxygen vacancies for efficient aerobic oxidation

Developing innovative catalysts for efficiently activating O2 into singlet oxygen (1O2) is a cutting-edge field with the potential to revolutionize green chemical synthesis. Despite its potential, practical implementation remains a significant challenge. In this study, we design a series of nitrogen (N)-doped manganese oxides (Ny-MnO2, where y represents the molar amount of the N precursor used) nanocatalysts using compartmentalized-microemulsion crystallization followed by post-calcination. These nanocatalysts demonstrate the remarkable ability to directly produce 1O2 at room temperature without the external fields. By strategically incorporating defect engineering and interstitial N, the concentration of surface oxygen atoms (Os) in the vicinity of oxygen vacancy (Ov) reaches 51.1% for the N55-MnO2 nanocatalyst. This feature allows the nanocatalyst to expose a substantial number of Ov and interstitial N sites on the surface of N55-MnO2, facilitating effective chemisorption and activation of O2. Verified through electron paramagnetic resonance spectroscopy and reactive oxygen species trapping experiments, the spontaneous generation of 1O2, even in the absence of light, underscores its crucial role in aerobic oxidation. Density functional theory calculations reveal that an increased Ov content and N doping significantly reduce the adsorption energy, thereby promoting chemisorption and excitation of O2. Consequently, the optimized N55-MnO2 nanocatalyst enables room-temperature aerobic oxidation of alcohols with a yield surpassing 99%, representing a 6.7-fold activity enhancement compared to ε-MnO2 without N-doping. Furthermore, N55-MnO2 demonstrates exceptional recyclability for the aerobic oxidative conversion of benzyl alcohol over ten cycles. This study introduces an approach to spontaneously activate O2 for the green synthesis of fine chemicals.

Unlocking Catalytic Potential: Encasing CoP Nanoparticles within Mesoporous CoFeP Nanocubes for Enhanced Oxygen Evolution Reaction

Efficient and durable electrocatalysts fabricated by using nanosized nonprecious-metal-based materials have attracted considerable attention for use in the oxygen evolution reaction (OER). Understanding performance disparities and structure-property relationships of various nonprecious-metal-based nanostructures is crucial for optimizing their applications. Herein, CoP nanoparticles encompassed within a CoFeP shell (named CoP/CoFeP) are fabricated. The mesoporous CoFeP shell enables effective mass transport, affords abundant active sites, and ensures the accessibility of hybrid interfaces between CoP and CoFeP. Therefore, encased CoP/CoFeP nanocubes exhibit excellent OER catalytic activity with an overpotential of 266 mV at a current density of 10 mA cm-2 in alkaline media, superior to reference hollow CoFeP nanocubes and commercial RuO2. Experimental characterization and theoretical calculations show that the encased structure of CoP/CoFeP with a rich Fe-doped shell enables electronic interactions between CoP and CoFeP, as well as accelerates structural reconstruction that exposes more active sites, yielding an enhanced OER performance. This study aims to inspire further work on nonprecious-metal catalysts with tailored nanostructures and electronic properties for the OER.

Materials Space-Tectonics: Atomic-level Compositional and Spatial Control Methodologies for Synthesis of Future Materials

Reactions occurring at surfaces and interfaces necessitate the creation of well-designed surface and interfacial structures. To achieve a combination of bulk material (i.e., framework) and void spaces, a meticulous process of "nano-architecting" of the available space is necessary. Conventional porous materials such as mesoporous silica, zeolites, and metal-organic frameworks lack advanced cooperative functionalities owing to their largely monotonous pore geometries and limited conductivities. To overcome these limitations and develop functional structures with surface-specific functions, the novel materials space-tectonics methodology has been proposed for future materials synthesis. This review summarizes recent examples of materials synthesis based on designing building blocks (i.e., tectons) and their hybridization, along with practical guidelines for implementing materials syntheses and state-of-the-art examples of practical applications. Lastly, the potential integration of materials space-tectonics with emerging technologies, such as materials informatics, is discussed.

Tensile Strain-Mediated Spinel Ferrites Enable Superior Oxygen Evolution Activity

Exploring efficient strategies to overcome the performance constraints of oxygen evolution reaction (OER) electrocatalysts is vital for electrocatalytic applications such as H2O splitting, CO2 reduction, N2 reduction, etc. Herein, tunable, wide-range strain engineering of spinel oxides, such as NiFe2O4, is proposed to enhance the OER activity. The lattice strain is regulated by interfacial thermal mismatch during the bonding process between thermally expanding NiFe2O4 nanoparticles and the nonexpanding carbon fiber substrate. The tensile lattice strain causes energy bands to flatten near the Fermi level, lowering eg orbital occupancy, effectively increasing the number of electronic states near the Fermi level, and reducing the pseudoenergy gap. Consequently, the energy barrier of the rate-determining step for strained NiFe2O4 is reduced, achieving a low overpotential of 180 mV at 10 mA/cm2. A total water decomposition voltage range of 1.52-1.56 V at 10 mA/cm2 (without iR correction) was achieved in an asymmetric alkaline electrolytic cell with strained NiFe2O4 nanoparticles, and its robust stability was verified with a voltage retention of approximately 99.4% after 100 h. Furthermore, the current work demonstrates the universality of tuning OER performance with other spinel ferrite systems, including cobalt, manganese, and zinc ferrites.

Mesoporous Metastable CuTe2 Semiconductor

Binary metastable semiconductor materials offer exciting possibilities in the field of optoelectronics, such as photovoltaics, tunable photosensors, and detectors. However, understanding their properties and translating them into practical applications can sometimes be challenging, owing to their thermodynamic instability. Herein, we report a temperature-controlled crystallization technique involving electrochemical deposition to produce metastable CuTe2 thin films that can reliably function under ambient conditions. A series of in situ heating/cooling cycle tests from room temperature to 200 °C followed by spectral, morphological, and compound analyses (such as ultraviolet-visible light spectroscopy, X-ray diffraction (XRD) analysis, and X-ray photoelectron spectroscopy (XPS)) suggest that the seeding electrodes play a key role in the realization of the metastable phase in CuTe2 films. In particular, CuTe2 films deposited on Al electrodes exhibit superior crystallinity and long-term stability compared with those grown on a Au substrate. The XRD data of thermally annealed CuTe2 thin films deposited on Al show a markedly sharp peak, indicating significantly increased crystal-domain sizes. Our method can be used to achieve the metastable phase of CuTe2 with a bandgap of 1.67 eV and offers outstanding photoresponsivity under different illumination conditions.

Open-Mouthed Hollow Carbons: Systematic Studies as Cobalt- and Nitrogen-Doped Carbon Electrocatalysts for Oxygen Reduction Reaction

Although hollow carbon structures have been extensively studied in recent years, their interior surfaces are not fully utilized due to the lack of fluent porous channels in the closed shell walls. This study presents a tailored design of open-mouthed particles hollow cobalt/nitrogen-doped carbon with mesoporous shells (OMH-Co/NC), which exhibits sufficient accessibility and electroactivity on both the inner and outer surfaces. By leveraging the self-conglobation effect of metal sulfate in methanol, a raspberry-structured Zn/Co-ZIF (R-Zn/Co-ZIF) precursor is obtained, which is further carbonized to fabricate the OMH-Co/NC. In-depth electrochemical investigations demonstrate that the introduction of open pores can enhance mass transfer and improve the utilization of the inner active sites. Benefiting from its unique structure, the resulting OMH-Co/NC exhibits exceptional electrocatalytic oxygen reduction performance, achieving a half-wave potential of 0.865 V and demonstrating excellent durability.

Water Activation in Solar-Powered Vapor Generation

Solar-powered vapor evaporation (SVG), based on the liquid-gas phase conversion concept using solar energy, has been given close attention as a promising technology to address the global water shortage. At molecular level, water molecules escaping from liquid water should overcome the attraction of the molecules on the liquid surface layer to evaporate. For this reason, it is better to reduce the energy required for evaporation by breaking a smaller number of hydrogen bonds or forming weak hydrogen bonds to ensure efficient and convenient vapor production. Many novel evaporator materials and effective water activation strategies have been proposed to stimulate rapid steam production and surpass the theoretical thermal limit. However, an in-depth understanding of the phase/enthalpy change process of water evaporation is unclear. In this review, a summary of theoretical analyses of vaporization enthalpy, general calculations, and characterization methods is provided. Various water activation mechanisms are also outlined to reduce evaporation enthalpy in evaporators. Moreover, unsolved issues associated with water activation are critically discussed to provide a direction for future research. Meanwhile, significant pioneering developments made in SVG are highlighted, hoping to provide a relatively entire chain for more scholars who are just stepping into this field.

High entropy alloying strategy for accomplishing quintuple-nanoparticles grafted carbon towards exceptional high-performance overall seawater splitting

High entropy alloys (HEAs), a novel class of material, have been explored in terms of their excellent mechanical properties. Seawater electrolysis is a step towards sustainable production of carbon-neutral fuels such as H2, O2, and industrially demanding Cl2. Herein, we report a practically viable FeCoNiMnCr HEA nanoparticles system grafted on a conductive carbon matrix for promising seawater electrolysis. The comprehensive kinetics analysis of the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and chlorine evolution reaction (CER) confirms the effectiveness of our system. As an electrocatalyst, HEAs grafted on carbon black show trifunctionality with promising kinetics, selectivity and enduring performance, towards seawater splitting. We optimize high entropy alloy decorated/grafted carbon black (HEACB) catalysts, studying their synthesis temperature to scrutinize the effect of alloy formation variation on the catalysis efficacy. During the catalysis, selectivity between two mutually competing reactions, CER and OER, in the electrochemical catalysis of seawater is controlled by the reaction media pH. We employ Mott-Schottky measurements to probe the band structure of the intrinsically induced metal-semiconductor junction in the HEACB catalyst, where the carrier density and flat band potential are optimized. The HEACB sample provides promising results towards overall seawater electrolysis with a net half-cell potential of about 1.65 V with good stability, which strongly implies its broad practical applicability.

Modulating Electronic Metal-Support Interactions to Boost Visible-Light-Driven Hydrolysis of Ammonia Borane: Nickel-Platinum Nanoparticles Supported on Phosphorus-Doped Titania

Ammonia borane (AB) is a promising material for chemical H2 storage owing to its high H2 density (up to 19.6 wt %). However, the development of an efficient catalyst for driving H2 evolution through AB hydrolysis remains challenging. Therefore, a visible-light-driven strategy for generating H2 through AB hydrolysis was implemented in this study using Ni-Pt nanoparticles supported on phosphorus-doped TiO2 (Ni-Pt/P-TiO2 ) as photocatalysts. Through surface engineering, P-TiO2 was prepared by phytic-acid-assisted phosphorization and then employed as an ideal support for immobilizing Ni-Pt nanoparticles via a facile co-reduction strategy. Under visible-light irradiation at 283 K, Ni40 Pt60 /P-TiO2 exhibited improved recyclability and a high turnover frequency of 967.8 molH 2 ${{_{{\rm H}{_{2}}}}}$  molPt -1  min-1 . Characterization experiments and density functional theory calculations indicated that the enhanced performance of Ni40 Pt60 /P-TiO2 originated from a combination of the Ni-Pt alloying effect, the Mott-Schottky junction at the metal-semiconductor interface, and strong metal-support interactions. These findings not only underscore the benefits of utilizing multipronged effects to construct highly active AB-hydrolyzing catalysts, but also pave a path toward designing high-performance catalysts by surface engineering to modulate the electronic metal-support interactions for other visible-light-induced reactions.

A general protocol for precise syntheses of ordered mesoporous intermetallic nanoparticles

Intermetallic nanomaterials consist of two or more metals in a highly ordered atomic arrangement. There are many possible combinations and morphologies, and exploring their properties is an important research area. Their strict stoichiometry requirement and well-defined atom binding environment make intermetallic compounds an ideal research platform to rationally optimize catalytic performance. Making mesoporous intermetallic materials is a further advance; crystalline mesoporosity can expose more active sites, facilitate the mass and electron transfer, and provide the distinguished mesoporous nanoconfinement environment. In this Protocol, we describe how to prepare ordered mesoporous intermetallic nanomaterials with controlled compositions, morphologies/structures and phases by a general concurrent template strategy. In this approach, the concurrent template used is a hybrid of mesoporous platinum or palladium and Korea Advanced Institute of Science and Technology-6 (KIT-6) (meso-Pt/KIT-6 or meso-Pd/KIT-6) that can be transformed by the second precursors under reducing conditions. The second precursor can either be a second metal or a metalloid/non-metal, e.g., boron/phosphorus. KIT-6 is a silica scaffold that is removed using NaOH or HF to form the mesoporous product. Procedures for example catalytic applications include the 3-nitrophenylacetylene semi-hydrogenation reaction, p-nitrophenol reduction reaction and electrochemical hydrogen evolution reaction. The synthetic strategy for preparation of ordered mesoporous intermetallic nanoparticles would take almost 5 d; the physical characterization by electron microscope, X-ray diffraction and inductively coupled plasma-mass spectrometry takes ~2 days and the function characterization depends on the research question, but for catalysis it takes 1-5 h.

Porous and Partially Dehydrogenated Fe2+ -Containing Iron Oxyhydroxide Nanosheets for Efficient Electrochemical Nitrogen Reduction Reaction (ENRR)

The design and development of efficient catalysts for electrochemical nitrogen reduction reaction (ENRR) under ambient conditions are critical for the alternative ammonia (NH3 ) synthesis from N2 and H2 O, wherein iron-based electrocatalysts exhibit outstanding NH3 formation rate and Faradaic efficiency (FE). Here, the synthesis of porous and positively charged iron oxyhydroxide nanosheets by using layered ferrous hydroxide as a starting precursor, which undergoes topochemical oxidation, partial dehydrogenated reaction, and final delamination, is reported. As the electrocatalyst of ENRR, the obtained nanosheets with a monolayer thickness and 10-nm mesopores display exceptional NH3 yield rate (28.5 µg h-1 mgcat. -1 ) and FE (13.2%) at a potential of -0.4 V versus RHE in a phosphate buffered saline (PBS) electrolyte. The values are much higher than those of the undelaminated bulk iron oxyhydroxide. The larger specific surface area and positive charge of the nanosheets are beneficial for providing more exposed reactive sites as well as retarding hydrogen evolution reaction. This study highlights the rational control on the electronic structure and morphology of porous iron oxyhydroxide nanosheets, expanding the scope of developing non-precious iron-based highly efficient ENRR electrocatalysts.

A 2D/2D heterojunction of ultrathin Pd nanosheet/MXene towards highly efficient methanol oxidation reaction: the significance of 2D material nanoarchitectonics

Two-dimensional (2D) Pd nanosheet-based catalysts have recently garnered widespread attention due to their high atom utilization efficiency. However, their catalytic ability and structural stability still require significant enhancement before they can be widely applied. In this study, we presented the rational design and controllable fabrication of a novel 2D/2D heterojunction, which consists of ultrathin Pd nanosheets (NSs) grown on the Ti3C2Tx MXene surface (Pd NSs/MXene). This heterostructure was achieved through a robust and convenient stereo-assembly strategy. The newly developed Pd NSs/MXene heterojunction not only provides numerous exposed active Pd atoms with an optimized electronic structure but also enables an intimate Pd/MXene interfacial interaction, ensuring a stable hybrid configuration. Consequently, the resulting Pd NSs/MXene heterojunction exhibits exceptional methanol oxidation properties. It possesses a large electrochemically active surface area, high mass and specific activities, and a long operating life, which are significantly superior to those of traditional Pd nanoparticle/carbon and Pd nanosheet/carbon catalysts. Theoretical simulations further reveal strong electronic interactions between the Pd nanosheet and MXene, which dramatically enhance the adsorption energy of the Pd component and simultaneously lower its d-band center. As a result, the Pd NSs/MXene heterojunction is less susceptible to CO poisoning. This work introduces a new 2D/2D heterojunction based on MXene and noble metallic materials and holds significance for the development of other novel heterojunctions, particularly within the realm of 2D material nanoarchitectonics.

[Acute Aortic Dissection Escaping Cardiac Tamponade due to Congenital Pericardial Defect:Report of a Case]

The natural course of Stanford type A acute aortic dissection (AAAD) has a poor prognosis. Early diagnosis is crucial, but in clinical practice some patients do not have typical symptoms, leading to a delay in diagnosis. We encountered a patient who complained only of shoulder pain and moderate respiratory distress. A chest computed tomography( CT) examination showed a dilated ascending aorta and a massive left hemothorax with minimal pericardial effusion. Intraoperative findings revealed aortic dissection of the ascending aorta and a congenital defect on the left pericardium. We performed graft replacement of the aortic root and ascending aorta. Usually, cardiac tamponade is a fatal complication of AAAD. However, in this case, the congenital pericardial defect drained the hemorrhage into the thoracic cavity and relieved cardiac tamponade. AAAD with a congenital pericardial defect may present clinically atypical. In this case, the patient could be saved by surgery without developing circulatory failure due to cardiac tamponade.

Magnetic Covalent Organic Framework Composites for Wastewater Remediation

Covalent organic frameworks (COFs) with high specific surface area, tailored structure, easy functionalization, and excellent chemical stability have been extensively exploited as fantastic materials in various fields. However, in most cases, COFs prepared in powder form suffer from the disadvantages of tedious operation, strong tendency to agglomerate, and poor recyclability, greatly limiting their practical application in environmental remediation. To tackle these issues, the fabrication of magnetic COFs (MCOFs) has attracted tremendous attention. In this review, several reliable strategies for the fabrication of MCOFs are summarized. In addition, the recent application of MCOFs as outstanding adsorbents for the removal of contaminants including toxic metal ions, dyes, pharmaceuticals and personal care products, and other organic pollutants is discussed. Moreover, in-depth discussions regarding the structural parameters affecting the practical potential of MCOFs are highlighted in detail. Finally, the current challenges and future prospects of MCOFs in this field are provided with the expectation to boost their practical application.

Soft-hard interface design in super-elastic conductive polymer hydrogel containing Prussian blue analogues to enable highly efficient electrochemical deionization

The poor cycling stability of faradaic materials owing to volume expansion and stress concentration during faradaic processes limits their use in large-scale electrochemical deionization (ECDI) applications. Herein, we developed a "soft-hard" interface by introducing conducting polymer hydrogels (CPHs), that is, polyvinyl alcohol/polypyrrole (PVA/PPy), to support the uniform distribution of Prussian blue analogues (e.g., copper hexacyanoferrate (CuHCF)). In this design, the soft buffer layer of the hydrogel effectively alleviates the stress concentration of CuHCF during the ion-intercalation process, and the conductive skeleton of the hydrogel provides charge-transfer pathways for the electrochemical process. Notably, the engineered CuHCF@PVA/PPy demonstrates an excellent salt-adsorption capacity of 22.7 mg g-1 at 10 mA g-1, fast salt-removal rate of 1.68 mg g-1 min-1 at 100 mA g-1, and low energy consumption of 0.49 kW h kg-1. More importantly, the material could maintain cycling stability with 90% capacity retention after 100 cycles, which is in good agreement with in situ X-ray diffraction tests and finite element simulations. This study provides a simple strategy to construct three-dimensional conductive polymer hydrogel structures to improve the desalination capacity and cycling stability of faradaic materials with universality and scalability, which promotes the development of high-performance electrodes for ECDI.