Fabrication of Three-Dimensional Multiscale Porous Alloy Foams at a Planar Substrate for Efficient Water Splitting

The electrolysis of water to produce hydrogen and oxygen is a simple and attractive approach to store renewable energies in the form of chemical fuels, in which the key fact depends on the innovative exploration of high-performance electrocatalysts. Herein, we describe a novel electrochemical deposition method for synthesizing three-dimensional NiCo, NiCu, and CoCu alloy foams at a planar electrode substrate for the hydrogen evolution reaction (HER) and NiFe alloy foam for the oxygen evolution reaction (OER). The electrodes are composed of multiscale porous structure caused by concomitant hydrogen gas bubbles evolved during cathodic deposition. The unique electrode structure is beneficial for exposing more catalytic active sites, enhancing mass transport, and accelerating dissipation of gas bubbles generated during water electrolysis. The two electrode alkaline water electrolyzers constructed with these alloy foams can afford a current density of 400 mA cm(-2) at a cell voltage of 1.73 V for Ni30Fe parallel to NiCo and at 1.71 V for Ni30Fe parallel to NiCu and exhibit excellent durability in prolonged bulk electrolysis. The strategy developed in this study highlights construction of three-dimensional, multiscale porous electrocatalysts at a planar electrode substrate which is significant for catalysis application.