Superaerophobic 0D nickel–2D ceria supported 316L for enhanced OER and HER activity

Abstract

Hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are critical in water splitting electrolysis. Hence, discovery and development of bi-functional electrocatalysts with high efficiency and low-cost of deployment is essential for sustainable energy conversion. These gas involving reactions such as OER, HER, and CO₂ reduction with diversified bubble behaviors are essential in energy conversion processes. Therefore, electrode design strategies to achieve superwetting (liquid-solid) could accelerate gas bubble evolution at the electrode-electrolyte interface. In this work, electrodeposition methodology was adopted to fabricate Ni/CeO₂ superaerophobic electrodes for bifunctional electrocatalysis. The self-supported nanocomposite electrodes demonstrate superaerophobic wetting and a significant increase in electrocatalytic activity. The Ni/CeO₂ electrocatalyst demonstrate excellent OER and HER performance at an overpotential of 335 mV and 310 mV respectively. A lowest Tafel slope of 91.1 mV/dec and 84.6 mV/dec was achieved for OER and HER activity. Furthermore, a 3–5 fold increase in electrochemical surface area is evidenced for Ni/CeO₂ compared to nickel and CeO₂ catalytic electrodes. The interplay of superwetting, high electrochemical active surface area and oxygen vacancies are determined for enhanced water splitting with good endurance over 24 h measured at 20 mA/cm². This study could provide additional insights for design and development of low-cost, self-supported high efficient electrocatalyst for water splitting.