Boron-doped graphene as electrocatalytic support for iridium oxide for oxygen evolution reaction

Abstract

The present work details the development of IrO₂ nanoparticles (nps) supported on B-doped reduced graphene oxide as an oxygen evolution reaction (OER) electrocatalyst for electrochemical water splitting. IrO₂ on boron-doped reduced graphene oxide (B-rGO) is synthesized via sequential steps of pyrolysis to prepare B-rGO and a hydrothermal method for modification of B-rGO with IrO₂ nps. With 2 wt% boron doping in graphene, a 0.10 V decrease in the OER onset potential is observed for IrO₂ catalysts on B-rGO (IrO₂-B-rGO). The Tafel slope for the OER on B-rGO is estimated to be 124.8 mV dec⁻¹, which is lower than that on IrO₂-rGO and suggests strong adsorption of intermediates such as OH on the IrO₂ surface by the B-doping of graphene in acidic solution. In this article, we demonstrate the effect of boron doping on the electronic structure modification of the IrO₂ nps, which is expected to generate more electrocatalytic centers and enhance the catalytic activity.