Efficient oxygen evolution reaction on RuO2 nanoparticles decorated onion-like carbon (OLC)

Abstract

Abstract Oxygen evolution reaction (OER) is an important half-cell reaction of the electrical water splitting, for its high overpotential associated with sluggish OER kinetics. Therefore, it is critical to develop highly active and durable electrocatalysts to reduce the overpotential. Herein, ultra-small RuO2 nanoparticles (NPs) supported on onion-like carbon (OLC) and carbon nanotube (CNT) are successfully synthesized by means of wet impregnation combined with annealing treatment, respectively. The microstructure characterization results showed OLC perfect graphitic carbon layer structure, and the RuO2 NPs supported on the OLC possess larger particle size compared with the RuO2 NPs supported on the CNT. Moreover, the electronic structure of Ru in RuO2/OLC was also optimized by the OLC support to be beneficial for the OER. The OER performance of the catalysts were investigated in 1 M KOH solution. The results show RuO2/OLC has a comparable OER activity to the commercial RuO2, but a significantly higher mass activity than the commercial RuO2. When compared with the RuO2/CNT, RuO2/OLC not only exhibits lower overpotential and Tafel slop, but also owns more active sites and higher TOF value, indicating the OLC support improved the OER activity of RuO2/OLC. Moreover, RuO2/OLC showed a superior stability compared with RuO2/CNT, which can be attributed to the excellent electrochemical oxidation-resistance of the OLC.