IrO2-graphene hybrid as an active oxygen evolution catalyst for water electrolysis

In the present work, graphene supported IrO2 catalyst (IrO2/RGO) has been synthesized by hydrothermal method in ethanol/water mixture solvent. X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests reveal that IrO2 is uniformly supported on RGO surface with ultrafine IrO2 nanoparticles (ca. 1.7 nm). Linear sweep voltammetry (LSV) tests indicate that the catalytic activity of IrO2/RGO hybrid towards oxygen evolution reaction (OER) is 2.3 times that of commercial IrO2. The superior OER activity of IrO2/RGO hybrid is attributed to the enhanced surface area and the improved electrical conductivity of IrO2 due to the introduction of graphene support. Lifetime tests demonstrate that IrO2/RGO hybrid has unexpectedly high OER durability. It also displays an excellent performance in long-time water electrolysis. This may be interpreted in terms of the dispersion retention of IrO2 nanoparticles on RGO surface, which is caused by the interaction between IrO2 and Π-electrons of RGO.