Coupling of Nickel Boride and Ni(OH)2 Nanosheets with Hierarchical Interconnected Conductive Porous Structure Synergizes the Oxygen Evolution Reaction

TLDR: In this paper, a hierarchical porous electrocatalyst structure utilizing Ni(OH)2 nanosheets directly synthesized on Ni foam as the conductive and interconnected supports was developed, which exhibited dramatically enhanced electrocatalytic activities and durabilities towards OER.

Abstract: Earth‐abundant and highly‐efficient electrocatalysts for oxygen evolution reaction (OER) are urgently desired to realize the large‐scale storage and conversion of renewable energies. In this work, we develop a hierarchical porous electrocatalyst structure utilizing Ni(OH)2 nanosheets directly synthesized on Ni foam as the conductive and interconnected supports. By coupling with amorphous Ni−B nanoparticles, this hybrid catalyst exhibits dramatically enhanced electrocatalytic activities and durabilities towards OER. In specific, along with the optimized Ni−B loading, this catalyst requires only an impressively small overpotential of 300 mV to drive a current density of 100 mA cm−2 for oxygen evolution in 1 M KOH electrolyte. Meanwhile, it also yields a small Tafel slope of 49 mV dec−1 and a superior long‐term stability. All these results evidently indicate that the hierarchical hybridization of Ni−B with Ni(OH)2 on Ni foam can effectively synergize the oxygen evolution, opening up a new vista for designing high‐performance transition metal‐based nanostructures in the field of electrochemical water splitting.