Non-oxygen anion-regulated in situ cobalt based heterojunctions for active alkaline hydrogen evolution catalysis

Abstract

More efficient cobalt-based catalysts are required for practically scalable clean energy technologies, especially in Hydrogen evolution reaction (HER). This is, however, an intimidating challenge that appeals to a general strategy to effectively regulate the catalytic activity of cobalt-based catalysts. Herein, a general strategy to enhance the HER properties of Co-based heterojunction catalysts with dual nanostructures on 3D Stainless steel mesh (SSM) through anionic regulation of the CoO parent compound with non-oxygen species is reported. The as-prepared CoO/CoX heterojunction catalysts (X = P, N, S) obtained exhibit better HER activity than the corresponding directly oxygen- and non-oxygen-treated catalysts. The optimized CoO-CoP on SSM (denoted SSM/CoOP) displays an overpotential of −21 [email protected] mA cm−2, exhibiting similar kinetics to the benchmark Pt-C catalysts (-19 mV). Due to the attractive OER performance of SSM/CoOP, a potential of 1.57 [email protected] mA cm−2 was achieved when SSM/CoOP was used as bifunctional catalysts in the overall water splitting device. The HER properties is enhanced due to the electronic coupling between CoO and CoX that significantly reduces the adsorption free energy, and the 1D-2D dual nanostructures that exposes the active sites and fasten the ion/electron transportation in the hybrid system.