A Setaria-inflorescence-structured catalyst based on nickel–cobalt wrapped silver nanowire conductive networks for highly efficient hydrogen evolution

Abstract

Generating hydrogen from electrocatalytic water electrolysis is one of the most promising approaches as a clean-energy alternative to earth-polluting fossil fuels, and it is critically important to develop high-efficiency and low-priced electrocatalysts. Here, for the first time, we demonstrate a new strategy, taking the catalytic system based on Ni–Co wrapped Ag nanowires (Ni–Co@Ag NWs) for highly effective hydrogen evolution reaction (HER) via in situ electrochemical co-deposition. The introduction of Ag NWs provides a barrier-free network as an expressway for electron transfer to numerous catalytic sites. The synergy effect between Ni, Co and Ag further lowers the energy barrier for facile hydrogen atom adsorption and hydrogen desorption. Meanwhile, the obtained catalyst has a unique Setaria-inflorescence-structure with the Ag core as the “rachis” and the Ni–Co shell as the “pinnules”, providing abundant active sites and mass transport pathways. Consequently, this system exhibits a highly efficient hydrogen evolution with an overpotential of ∼33 mV at 10 mA cm⁻², which is, to the best of our knowledge, the lowest value compared with those reported previously for Ni–Co binary catalysts. This work presents a new strategy to design high-performance and low-cost metal-based catalysts for the HER.