Sulfurization-Promoted Surface Reconstruction of CoAl Layered Hydroxide Nanostructures for Alkaline Water Oxidation

The development of high-performance and stable electrocatalysts for the oxygen evolution reaction (OER) is challenging. Herein, this paper reports the construction of nanostructures (S 0.5 -Co 3 Al-LDH/nickel foam (NF)) on NF by a two-step hydrothermal method for alkaline water oxidation. The three-dimensional nanoflower structure provides a large number of active sites, which facilitate full electrolyte contact, rapid charge and mass transfer, and synergistic promotion of alkaline water oxidation. The S 0.5 -Co 3 Al-LDH/NF nanomaterials showed significant OER catalytic activity in a 1.0 M KOH solution, with a smaller overpotential (279 mV) and a Tafel slope of 32 mV dec –1 at a current density of 25 mA cm –2 as compared to the Co 3 Al-LDH/NF composite (306 mV). In addition, Al 3+ was etched away by OH – during the OER process, generating M 3+ vacancies, which facilitated transport of OH – to the electrode surface, thus enhancing the oxygen precipitation reaction activity. This study provides ideas for the design of OER catalysts with a particular focus on the surface morphology of the catalysts.