Fabrication of highly stable Ni-Ni/Ta composite micron-scale catalysts for efficient oxygen evolution by magnetic field-assisted electrodeposition

Abstract

In recent years, the growing demand for green energy that is both non-polluting and sustainable has prioritized the search for catalysts that are inexpensive and easy to produce for the process of overall water splitting. We have found that the non-precious metal, Ta, has remarkable electrical conductivity. By using density functional theory, we have determined that the coupling of Ni and Ta can synergistically enhance the electrolysis of water. To create a composite electrode with hydrophilic properties, we employed a magnetic field-assisted electrodeposition technique, which resulted in the formation of composite particles made up of Ni nanoparticles wrapped around Ta micron-cone particles on the surface of the Ni electrode. This composite electrode exhibited exceptional performance, requiring only 256 mV overpotential at a current density of 10 mA∙cm−2 in the oxygen evolution reaction (OER), with a Tafel slope of 51 mV∙dec−1. Additionally, the composite electrode displayed remarkable stability during 30 h of continuous electrolysis, retaining over 95 % of its current. This study offers a promising approach for designing non-precious metal catalysts with micro- and nanostructures.