Photo-assisted electrocatalysis of NiO/CeO2 heterojunction for efficient oxygen evolution reaction

In recent years, photo-assisted electrocatalysis has attracted significant interest in the field of electrolytic hydrogen production. By integrating electrical and optical energy, supplementary energy is harnessed for the electrocatalytic process, which offers an efficient strategy to enhance the performance of oxygen evolution reaction (OER). Herein, the heterojunction NiO/CeO2 composite nanostructures supported by nickel foam (represented as NiO/CeO2@NF) was selected as the photo-assisted electrocatalyst, through the mutual synergy of voltage and light to improve the catalytic activity of OER in electrolytic water. Under light irradiation, the NiO component undergoes photoexcited to produce photogenerated electrons that move towards the CeO2 component, stimulating the generation and accumulation of more holes accelerating the formation of Ni (III) to improve the reaction efficiency with electrons, thereby boosting the enhancement of OER activity. The results demonstrate that the overpotential corresponding to NiO/CeO2@NF in non-irradiation at 10 mA cm-2 current density was 280 mV, and the NiO/CeO2@NF in light irradiation displays robust OER activity, with lower over-potentials 260 mV at 10 mA cm-2, which 20 mV lower than in non-irradiation. Moreover, NiO/CeO2@NF in light irradiation exhibits high catalytic activity and durability for OER in an alkaline electrolyte, delivering 100 mA cm-2 at 320 mV and outperforming RuO2 under high current densities.