Water oxidation catalysts from electrochemical intercalating [PW12O40]3‐ and synthesizing layered double hydroxide on high conductivity rGO@Ni foam

Abstract

Developing an efficient and durable water oxidation catalyst is essential for the large-scale application of water electrolysis technologies. Novel catalysts, NF@rGO-LDH-PWs, were constructed through the electrochemical synthesis of Keggin-structure [PW₁₂O₄₀]³⁻ intercalated layered double hydroxide (LDH) arrays on porous nickel foams coated with reduced graphene oxide (rGO). The optimized intrinsic properties, such as enhanced conductivity, modulated electronic structure and constructed abundant diffusion paths, endow the hetero-structure catalyst with noteworthy oxygen evolution reaction (OER) performances in alkaline medium. Under optimal conditions, the catalyst exhibited an overpotential of 223 mV at 10 mA cm⁻², a Tafel slope of 33 mV dec⁻¹, an exchange current density of 8.3 × 10⁻² mA cm⁻², an activation energy of 14.60 kJ mol⁻¹ and a double-layer capacitance of 12.31 mF cm⁻², all of which are superior to those of its single-component counterparts. The turnover frequency (TOF) reached 0.38 s⁻¹, which is approximately 5 times higher than that of the substrate materials. Furthermore, the catalyst demonstrated excellent stability, with a relative standard deviation of only 0.09 % during 12 h of continuous operation.