Publications by authors named "Xiongwu Kang"

Facets engineering of high entropy alloy (HEA) nanocrystals might be achieved via shape-controlled synthesis, which is promising but remains challenging in designing Ir-based catalysts towards efficient and robust oxygen evolution reaction (OER) in acidic medium. Herein, icosahedra nanocrystals featured with PdCu core and IrPdCuFeNiCoMo shell were prepared by wet-chemical reduction in one-pot, ascribing to the initial formation PdCu core and subsequent deposition and diffusion of IrPdCuFeNiCoMo HEA shell. Sequential selective chemical etching of PdCu core results in IrPdCuFeNiCoMo HEA nanocages, delivering an overpotential of 235 mV at 10 mA cm, 51.

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Article Synopsis
  • Prussian blue analogs (PBAs) are gaining interest for their ability to activate peroxydisulfate (PDS) in degrading organic pollutants, specifically methylene blue (MB).
  • A series of Fe-Co PBAs with varying iron/cobalt ratios were synthesized and demonstrated high performance in PDS activation and recyclable efficiency.
  • Density functional theory calculations indicated that the interaction between the catalysts and the compounds being degraded enhances catalytic activity by facilitating easier electron transfer and adsorption.
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It is challenging to achieve highly efficient CO-CO coupling toward C products in electrochemical CO and CO reductions on single-atom catalysts (SACs). Herein, we report a modulation strategy of phosphorus coordination in the second shell of Cu SACs with a Cu-N structure (Cu-N-P/C) and demonstrate experimentally and theoretically the CO-CO coupling through an Eley-Rideal mechanism in electrochemical CO reduction (COR). Remarkably, the Cu SACs exhibit a selectivity of 63.

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Integrating high-entropy philosophy and nanocrystal-specific orientation into a single catalyst represents a promising strategy in development of high-performance catalysts. Nonetheless, shape-controlled synthesis of high-entropy alloy (HEA) nanocrystals is challenging owing to the distinct redox potentials and growth dynamics of metal elements. Herein, a one-pot co-reduction method is developed to fabricate ruthenium (Ru)-doped PtFeNiCuW octahedral HEA nanocrystals onto carbon nanotubes (Ru-PtFeNiCuW/CNTs).

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High entropy metal oxides (HEO) are superior to many reactions involving multi-step elementary reactions. However, controlled synthesis of hollow-structured HEO catalysts, which offers large surface area and fast mass transfer kinetics, remains challenging and unexplored due to the complicated metal precursors. Herein, a metal organic framework-templated synthesis of hollow-structured and polyhedron-shaped HEO catalysts assembled with ultra-small nanoparticles, with up to ten metal elements, can be achieved, by taking advantage of the ion-exchange method.

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Electrocatalytic reduction of CO (CORR) to value-added fuels and chemicals can potentially serve as a promising strategy to curb CO accumulation and carbon neutral cycle, but is still plagued by sluggish kinetics, poor selectivity and weak durability. Herein, we developed highly-dispersed nickel species on the nitrogen-doped carbon materials (Ni/NC) via the double solvent method (DSM), followed by the pyrolysis. The as-prepared Ni/NC possesses high CO-to-CO selectivity of 93.

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Two-dimensional black phosphorus (BP) has emerged as a perspective material for various micro- and opto-electronic, energy, catalytic, and biomedical applications. Chemical functionalization of black phosphorus nanosheets (BPNS) is an important pathway for the preparation of materials with improved ambient stability and enhanced physical properties. Currently, the covalent functionalization of BPNS with highly reactive intermediates, such as carbon-free radicals or nitrenes, has been widely implemented to modify the material's surface.

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Potassium ion batteries (PIBs) have great potential to replace lithium ion batteries (LIBs) for large-scale energy storage applications because of the low cost and earth abundance of potassium resources. However, it is critically challenging to exploit an appropriate cathode material to accommodate the large size of K. Herein, a conducting polymer (PEDOT) intercalation method is utilized to tailor the interlayer spacing of NHVO nanobelts from 7.

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Hot carriers generated by localized surface plasmon resonance (LSPR) excitation of plasmonic metal nanoparticles are known to enhance electrocatalytic reactions. However, the participation of plasmonically generated carriers in interfacial electrochemical reactions is often limited by fast relaxation of these carriers. Herein, we address this challenge by tuning the electronic structure of a plasmonic electrocatalyst.

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High entropy alloy (HEA) catalysts exhibit excellent multifunctional catalytic performance due to the synergistic effect of multi-metal components. However, shape-controlled synthesis of such kinds of HEA catalysts, especially those with high index facets, still faces great challenges, limiting further enhancement of their catalytic performance. Herein, one-pot synthesis of convex cube-shaped Pt Fe Ni Cu Mo Ru HEA catalysts which possess rich (310) facets and a diagonal crystalline size of 38.

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Doping metal nanoclusters (NCs) with another metal usually leads to superior catalytic performance toward CO reduction reaction (CORR), yet elucidating the metal core effect is still challenging. Herein, we report the systematic study of atomically precise alkynyl-protected AuAg, AgCu, and AuAgCu NCs toward CORR. AuAgCu prepared by a site-specific metal exchange approach from AgCu is the first case of trimetallic superatom with full-alkynyl protection.

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The redox center of transition metal oxides and hydroxides is generally considered to be the metal site. Interestingly, proton and oxygen in the lattice recently are found to be actively involved in the catalytic reactions, and critically determine the reactivity. Herein, taking glycerol electrooxidation reaction as the model reaction, we reveal systematically the impact of proton and oxygen anion (de)intercalation processes on the elementary steps.

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Transition metal phosphides (TMPs) are promising anode candidates for sodium-ion batteries, due to their high theoretical specific capacity and working potential. However, the low conductivity and excessive volume variation of TMPs during insertion/extraction of sodium ions result in a poor rate performance and long-term cycling stability, largely limiting their practical application. In this paper, NiP nanoparticles encapsulated in three-dimensional graphene (NiP @rGO) were obtained from the flower-like spherical α-Ni(OH) by phosphating and carbon encapsulation processes.

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In this manuscript, ruthenium (Ru) nanoparticles functionalized with nitrene ligands through the ruthenium-nitrene (RuN) π bonds are explored. By synthesizing the nitrene ligands with and without N-labelling, RuN π bonds on Ru nanoparticles are evidenced by experimental and theoretically calculated FTIR spectra. The coordination of nitrene ligands on Ru nanoparticles surface, the interfacial charge delocalization and the impact of nitrene ligands on the catalytic performance of Ru nanoparticles are further characterized by magic-angle spinning solid-state carbon nuclear magnetic resonance spectroscopy (C NMR) of CO-adsorbed Ru nanoparticles, photoluminescence and the hydrogenation of styrene.

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Binary transition metal selenides have been more promising than single transition metal selenides as anode materials for sodium-ion batteries (SIBs). However, the controlled synthesis of transition metal selenides, especially those derived from metal-organic-frameworks with well-controlled structure and morphology is still challenging. In this paper, highly porous NiCoSe @NC composite microspheres were synthesized by simultaneous carbonization and selenization of a Ni-Co-based metal-organic framework (NiCo-MOF) and characterized by scanning electron microscopy, transition electron microscopy, X-Ray diffraction, X-Ray photoelectron spectroscopy and electrochemical techniques.

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It is desirable to unravel the correlation between the geometric and electronic structures and the activity and further prepare high-performance electrocatalysts. Here in this paper, trimetallic Ru@Au-Pt core-shell nanoparticles were prepared by sequential ethanol reduction method, and further subject to characterization of X-ray diffraction, high angle annular dark field transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical CO stripping. Further analysis based on Williamson-Hall method revealed that the Au/Pt atomic ratio and shell thickness result in apparent variation of micro-strain and CO binding energy of Ru@AuPt nanoparticles, where the CO oxidation peak potential showed an inverted volcano-shape dependence on the microstrain of the metal nanoparticles while the catalytic activity towards electrooxidation of formic acid is linearly dependent on the micro-strain.

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Constructing a solid electrolyte interface (SEI) is a highly effective approach to overcome the poor reversibility of lithium (Li) metal anodes. Herein, an adhesive and self-healable supramolecular copolymer, comprising of pendant poly(ethylene oxide) (PEO) segments and ureido-pyrimidinone (UPy) quadruple-hydrogen-bonding moieties, is developed as a protection layer of Li anode by a simple drop-coating. The protection performance of in-situ-formed LiPEO-UPy SEI layer is significantly enhanced owing to the strong binding and improved stability arising from a spontaneous reaction between UPy groups and Li metal.

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Localized surface plasmon resonance (LSPR) excitation of noble metal nanoparticles has been shown to accelerate and drive photochemical reactions. Here, LSPR excitation is shown to enhance the electrocatalysis of a fuel-cell-relevant reaction. The electrocatalyst consists of Pd Ag alloy nanotubes (NTs), which combine the catalytic activity of Pd toward the methanol oxidation reaction (MOR) and the visible-light plasmonic response of Ag.

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The recognition of the solid electrolyte interface (SEI) between the electrode materials and electrolyte is limiting the selection of electrode materials, electrolytes, and further the electrochemical performance of batteries. Herein, we report ZnSe@C core-shell nanocomposites derived from ZIF-8 as anode materials of lithium-ion batteries, the electrochemical performances, and SEI films formed on ZnSe@C in both ether and carbonate electrolytes. It is found that ZnSe@C delivers a reversible capacity of 617.

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It is of fundamental and technological significance to develop dual-role anode materials for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) with high performance. Here, a composite material based on CoSe nanoparticles encapsulated in N-doped carbon framework intertwined with carbon nanotubes (CoSe@N-CF/CNTs) is prepared successfully from cobalt-based zeolitic imidazolate framework (ZIF-67). As anode materials for LIBs, CoSe@N-CF/CNTs composites deliver a reversible capacity of 428 mAh g even after 500 cycles at a current density of 1 A g with almost 100% Coulombic efficiency.

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Photoinduced charge transfer across the metal oxide-organic ligand interface plays a key role in the diverse applications of metal oxide nanomaterials/nanostructures, such as photovoltaics, photocatalysis, and optoelectronics. Thus far, most studies are focused on molecular engineering of the organic chromophores, where the charge-transfer properties have been found to dictate the photo absorption efficiency and eventual device performance. Yet, as the chromophores are mostly bound onto the metal oxide surfaces by hydroxyl or carboxyl anchors, the impacts of the bonding interactions at the metal oxide-ligand interface on interfacial charge transfer have remained largely unexplored.

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Developing high surface area nanostructured electrodes with fast charge separation is one of the main challenges for exploring cupric oxide (CuO)-based photocathodes in solar-driven hydrogen production applications. Herein, brand new 1D branched CuO nanowire arrays have been achieved on fluorine-doped tin oxide-coated glass (FTO) through a two-step wet chemical redox reaction. X-ray diffraction patterns, Raman spectra and X-ray photoelectron spectroscopy confirm the pure phase characteristic of the resulting branched CuO.

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Nitrogen and sulfur-codoped graphene composites with Co S (NS/rGO-Co) are synthesized by facile thermal annealing of graphene oxides with cobalt nitrate and thiourea in an ammonium atmosphere. Significantly, in 0.1 m KOH aqueous solution the best sample exhibits an oxygen evolution reaction (OER) activity that is superior to that of benchmark RuO catalysts, an oxygen reduction reaction (ORR) activity that is comparable to that of commercial Pt/C, and an overpotential of only -0.

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Noble metal nanoparticles represent a unique class of functional nanomaterials with physical and chemical properties that deviate markedly from those of their atomic and bulk forms. In order to stabilize the nanoparticles and further manipulate the materials properties, surface functionalization with organic molecules has been utilized as a powerful tool. Among those, mercapto derivatives have been used extensively as the ligands of choice for nanoparticle surface functionalization by taking advantage of the strong affinity of thiol moieties to transition metal surfaces forming (polar) metal-thiolate linkages.

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Nanocomposites based on p-mercaptobenzoic acid-functionalized gold nanoclusters, Au102(p-MBA)44, and porous carbon nanosheets have been fabricated and employed as highly efficient electrocatalysts for oxygen reduction reaction (ORR). Au102(p-MBA)44 clusters were synthesized via a wet chemical approach, and loaded onto carbon nanosheets. Pyrolysis at elevated temperatures led to effective removal of the thiolate ligands and the formation of uniform nanoparticles supported on the carbon scaffolds.

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