Ultrathin, Porous and Oxygen Vacancies‐Enriched Ag/WO_3−x Heterostructures for Electrocatalytic Hydrogen Evolution

Abstract

Exploring advanced electrocatalysts for electrocatalytic hydrogen evolution is highly desired but remains a challenge due to the lack of an efficient preparation method and reasonable structural design. Herein, we deliberately designed novel Ag/WO3−x heterostructures through a supercritical CO2‐assisted exfoliation‐oxidation route and the subsequent loading of Ag nanoparticles. The ultrathin and oxygen vacancies‐enriched WO3−x nanosheets are ideal substrates for loading Ag nanoparticles, which can largely increase the active site density and improve electron transport. Besides, the resultant WO3−x nanosheets with porous structure can form during the electrochemical cycling process induced by an electric field. As a result, the exquisite Ag/WO3−x heterostructures show an enhanced hydrogen evolution reaction (HER) activity with a low onset overpotential of ≈30 mV, a small Tafel slope of ≈40 mV dec−1 at 10 mA cm−2, and as well as long‐term durability. This work sheds light on material design and preparation, and even opens up an avenue for the development of high‐efficiency electrocatalysts.

Design Principles for Tungsten Oxide Electrocatalysts for Water Splitting

“…In addition to regulate the electronic structure of tungsten oxide, oxygen vacancies could also work as a stabilizer for Ag nanoparticles with high dispersion and mass activity. A novel Ag/WO 3‐x heterostructure was designed through a CO 2 assisted exfoliation‐oxidation route, and shows an enhanced HER activity with η 10 =30 mV and a small Tafel slope of ∼40 mV dec −1 [92] . In summary, the construction of oxygen vacancies is an effective strategy to enhance the catalytic performance by modulating the electronic structure.…”

“…η 10 = 30 mV and a small Tafel slope of ~40 mV dec À 1 . [92] In summary, the construction of oxygen vacancies is an effective strategy to enhance the catalytic performance by modulating the electronic structure. Moreover, the qualitative and quantitative characterizations of oxygen vacancies require mutual verification of various advanced techniques, such as UV-vis, TGA, XPS, Raman, XAS and EPR.…”

Catalytically active silver nanoparticles stabilized on a thiol-functionalized metal–organic framework for an efficient hydrogen evolution reaction

“…Moreover, the cost-effectiveness and the Earth abundance are the added advantages of silver. Several nanostructured silver and Ag-based catalysts like silver nanoparticles on TiO 2 , 36 the Ag 2 O/MoO 3 dendritic catalytic system, 37 Ag 2 S/MoS 2 nanocomposites anchored on reduced graphene oxide, 38 Ag/WO 3− x heterostructures, 39 the Ag/MgO nanocatalyst, 40 Ag NPs on silica supports, 41 the porous Ag/Ag 2 S nanostructure, 42 the Ag 2 S nanocrystal/reduced graphene oxide interface, 43 etc . have been devised for sustainable HER.…”

Engineering Coupled NiSx‐WO2.9 Heterostructure as pH‐Universal Electrocatalyst for Hydrogen Evolution Reaction

“…[11][12][13] W 6 + has a unique coordination configuration with outermost vacant orbitals, which is favorable to binding water molecules or reaction intermediates, offering a promising platform to tune the electronic structures. [14][15][16] However, the HER catalytic activity of simple WO 3 is far from satisfactory; optimizing the surface structure by chemical regulation is one of the important ways to improve its performance. In this regard, oxygen defect engineering is a general strategy to adjust the electronic structure, surface active sites, and the adsorption of reactant molecules of metal oxides, presenting great application prospects for HER.…”

“…Tungsten (W)‐based materials, especially the typical representative WO 3 with a high valence state of W 6+ , are considered promising candidates for HER due to the Earth‐abundant reserves [11–13] . W 6+ has a unique coordination configuration with outermost vacant orbitals, which is favorable to binding water molecules or reaction intermediates, offering a promising platform to tune the electronic structures [14–16] . However, the HER catalytic activity of simple WO 3 is far from satisfactory; optimizing the surface structure by chemical regulation is one of the important ways to improve its performance.…”