IrO2-ZnO Hybrid Nanoparticles as Highly Efficient Trifunctional Electrocatalysts

Abstract

Development of high-performance catalysts is very crucial for the commercialization of sustainable energy conversion technologies. Searching for stable, highly active, and low-cost multifunctional catalysts has become a critical issue. In this study, we report the synthesis of IrO2-ZnO hybrid nanoparticles and their highly efficient electrocatalytic. activities toward oxygen/hydrogen evolution reaction (OER/HER) as well as oxygen reduction reaction (ORR). For comparison, we synthesized RuO2-ZnO, showing a smaller catalytic activity than IrO2-ZnO, which provides robust evidence for the unique synergic effect of these hybrid structures. IrO2-ZnO and RuO2-ZnO exhibit excellent OER catalytic performance with Tafel slopes of 57 and 59 mV decade(-1), respectively. For HER, IrO2-ZnO shows a higher catalytic activity than RuO2-ZnO. The numbers of electrons involved in the ORR were 3,7 and 2.8, respectively, for IrO2-ZnO and RuO2-ZnO. The remarkable catalytic performance of IrO2-ZnO would be ascribed to the abundant oxygen vacancies and the metallic states of Ir, which ensure excellent catalytic activity and stability.