Sulfurization-Promoted\nSurface Reconstruction of CoAl\nLayered Hydroxide Nanostructures for Alkaline Water Oxidation

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