Contribution of B,N-co-doped reduced graphene oxide as a catalyst support to the activity of iridium oxide for oxygen evolution reaction†
Abstract
The current research deals with the study of boron and nitrogen co-doped reduced graphene oxide (BN-rGO) as a support material for iridium oxide (IrO2) nanoparticles for oxygen evolution reaction (OER) catalysis. The synthetic approach for the IrO2–BN-rGO catalyst involves the combination of pyrolysis and hydrothermal methods used for hierarchical nanostructures. BN-rGO possesses B–N, B–C, and N–C functional groups to support and stabilize the IrO2 catalyst nanoparticles. The altered electronic states of IrO2 on the BN-rGO support are compared with those of IrO2 on a non-doped support, rGO (IrO2–rGO), and on commercial BN sheets (IrO2–c-BN). The catalyst shows a low overpotential (300 mV at 10 mA cm−2), high current density (55 mA cm−2 at 1.65 V), and significantly high durability (12 350 cycles; 45 h) in an acidic environment. The high stability of IrO2–BN-rGO may result from the presence of a chemically and electrochemically stable B–N bond. We confirm that other functional groups (B–C and N–C) and the rGO framework are equally crucial for better attachment of IrO2 nanoparticles.