Tuning wettability of nickel-based electrode by micro-nano surface structure to boost OER catalysis

Electrolysis of water is a green and environmentally friendly hydrogen production method, but its low oxygen evolution reaction (OER) efficiency hinders its large-scale application. A major strategy to improve the catalytic performance of OER is constructing the micro-nano structure on the surface of the catalyst. However, the exact effects of micro-nano surface structure, such as roughness, morphology and hierarchical structure on the catalytic performance have not been systematically studied. Herein, Nickel-Cobalt-Cerium Oxide (Ni-Co-CeO2) catalytic electrodes with the different micro-nano surface structures are fabricated by magnetic field-induced scanning electrodeposition. The effects of the micro-nano surface structure on catalytic performance are investigated. The results show that the micro-nano surface structure of Ni-Co-CeO2 catalytic electrodes has a great influence on the wetting state, which may lead to the Wenzel-Cassie transition, resulting in severe degradation of catalytic performance. By optimizing the micro-nano surface structure, the Ni-Co-CeO2 catalytic electrode has the best catalytic performance with the overpotential of 309 mV for OER to achieve the current density of 10 mA/cm2 and the corresponding Tafel slopes of 39.52 mV/dec. The study also demonstrates that the magnetic field-induced scanning electrodeposition is an efficient and simple method for tuning the micro-nano surface structure of electrodes to boost the OER efficiency.