Enriched oxygen vacancy promoted heteroatoms (B, P, N, and S) doped CeO2: Challenging electrocatalysts for oxygen evolution reaction (OER) in alkaline medium

Abstract

Increasing worldwide energy consumption has prompted considerable study into energy generation and energy storage systems in recent years. Chemical fuels may be produced efficiently via electrocatalytic water splitting, which uses electric and solar power. The development of efficient anodic electrocatalysts for efficient oxygen evolution reaction (OER) is a greater concern of present energy research. Cerium oxide (CeO2) are promising electrocatalysts that exhibit outstanding OER but their reduced stability obstructs the practical application. A novel strategy was established to construct an effective catalyst of heteroatom (N, B, P and S) doped CeO2 matrix were prepared. Moreover, the doping of heteroatoms into the CeO2 matrix processes the improved electronic conductivity, reactive sites, increases the electrochemical catalytic activity, which enhances the water oxidation reaction. Consequently, well-suited alkaline electrolysers were brought together for water oxidation to ideal OER electrocatalytic activity. The OER activity of the electrocatalysts follows the order of S–CeO2 (190 mV@10 mA cm−2), N– CeO2 (220 mV @10 mA cm−2), P– CeO2 (230 mV @10 mA cm−2), B–CeO2 (250 mV @10 mA cm−2) and CeO2 (260 mV @10 mA cm−2) in 1 M of KOH. From the kinetics analysis, Tafel slope value achieved for catalysts CeO2, B–CeO2, P–CeO2, N–CeO2 and S–CeO2 are 142 mV dec−1,121 mV dec−1, 102 mV dec−1, 98 mV dec−1 and 83 mV dec−1 respectively. These results validate that the S–CeO2 electrode is prominent for OER performance with the requirement of cell voltage of 1.42 V at 10 mA cm−2 current density. In addition, sulphur doped CeO2 relatively have excellent stability through chrono-potentiometric analysis lasting for 20 h. Although the heteroatoms doped CeO2 is acts as anode material, the preparation method is widespread, which will reduce the synthesis cost and streamline the preparation of electrode for OER. This research effort delivers a complete advantage for the development of robust, environmentally friendly and highly dynamic electrocatalysts for OER activity.