Nanoporous Surface High-Entropy Alloys as Highly Efficient Multisite Electrocatalysts for Nonacidic Hydrogen Evolution Reaction

Electrocatalytic hydrogen evolution in alkaline and neutral media offers the possibility of adopting platinum-free electrocatalysts for large-scale electrochemical production of pure hydrogen fuel, but most state-of-the-art electrocatalytic materials based on nonprecious transition metals operate at high overpotentials. Here, a monolithic nanoporous multielemental CuAlNiMoFe electrode with electroactive high-entropy CuNiMoFe surface is reported to hold great promise as cost-effective electrocatalyst for hydrogen evolution reaction (HER) in alkaline and neutral media. By virtue of a surface high-entropy alloy composed of dissimilar Cu, Ni, Mo, and Fe metals offering bifunctional electrocatalytic sites with enhanced kinetics for water dissociation and adsorption/desorption of reactive hydrogen intermediates, and hierarchical nanoporous Cu scaffold facilitating electron transfer/mass transport, the nanoporous CuAlNiMoFe electrode exhibits superior nonacidic HER electrocatalysis. It only takes overpotentials as low as approximate to 240 and approximate to 183 mV to reach current densities of approximate to 1840 and approximate to 100 mA cm(-2) in 1 m KOH and pH 7 buffer electrolytes, respectively; approximate to 46- and approximate to 14-fold higher than those of ternary CuAlNi electrode with bimetallic Cu-Ni surface alloy. The outstanding electrocatalytic properties make nonprecious multielemental alloys attractive candidates as high-performance nonacidic HER electrocatalytic electrodes in water electrolysis.

Automated summary

This study introduces a novel monolithic nanoporous multielemental CuAlNiMoFe electrode with a high-entropy CuNiMoFe surface as a cost-effective electrocatalyst for hydrogen evolution reaction in alkaline and neutral media. The electrode, with a surface high-entropy alloy and hierarchical nanoporous Cu scaffold, exhibits superior nonacidic HER electrocatalysis.