In situ formed nickel tungsten oxide amorphous layer on metal–organic framework derived ZnxNi1−xWO4 surface by self-reconstruction for acid hydrogen evolution reaction.

In situ surface reconstruction strategy is developed to construct efficient acidic HER catalyst during the electrocatalytic process. By exploring the evolution of the catalyst, it is found that Ni-W-O amorphous layer is formed on the catalyst surface and serves as the actual active species. The synergistic effect between Ni and W modulates the electron structure of the in situ formed Ni-W-O amorphous surface layer, which may moderate the hydrogen adsorption Gibbs free energy and improve the HER catalytic activity. [Display omitted] • Efficient acidic HER catalyst is developed by an in situ surface reconstruction strategy during the electrocatalytic process. • The active species is identified to be Ni-W-O amorphous surface layer by exploring the evolution of the catalyst. • The synergistic effect between Ni and W modulates the electron structure of the in situ formed Ni-W-O amorphous surface layer. Noble metal free electrocatalysts for hydrogen evolution reaction (HER) in acid play an important role in proton exchange membrane-based electrolysis. Here, we develop an in situ surface self-reconstruction strategy to construct excellent acidic HER catalysts. Firstly, free-standing zinc nickel tungstate nanosheets inlaid with nickel tungsten alloy nanoparticles were synthesized on carbon cloth as pre-catalyst via metal–organic framework derived method. Amorphous nickel tungsten oxide (Ni-W-O) layer is in situ formed on surface of nanosheet as actual HER active site with the dissolution of NiW alloy nanoparticles and the leaching of cations. While the morphology of the free-standing structure remains the same, keeping the maximized exposure of active sites and serving as the electron transportation framework. As a result, benefiting from disordered arrangement of atoms and the synergistic effect between Ni and W atoms, the amorphous Ni-W-O layer exhibits an excellent acidic HER activity with only an overpotential of 46 mV to drive a current density of 10 mA cm−2 and a quite good Tafel slope of 36.4 mV dec−1 as well as an excellent durability. This work enlightens the exploration of surface evolution of catalysts during HER in acidic solution and employs it as a strategy for designing acidic HER catalysts. [ABSTRACT FROM AUTHOR]