Investigation of β-SiC as an anode catalyst support for PEM water electrolysis

Because iridium is both expensive and scarce, it is essential to reduce the amount of IrO2 in the anode catalysts of polymer electrolyte membrane water electrolysers (PEMWEs). The potential of beta-SiC to act as a catalyst support for PEMWE anodes was evaluated. To do so, a modified version of the Adams fusion method was used to prepare catalysts with IrO2 supported on beta-SiC with a mass percentage of IrO2 of 20, 40, 50, 60, 70, 80, 90, and 100 %. The thin-film method was used for the electrochemical characterization of catalysts by cyclic and linear sweep voltammetry. The catalysts were further characterized by scanning electron microscopy/energy dispersive X-ray (SEM-EDX) analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and N-2 adsorption (BET). Gas diffusion electrodes with the synthesized catalysts were prepared for tests in a laboratory PEMWE. A 10 % improvement over pure IrO2 was found in a supported catalyst with 80 wt.% IrO2. However, such a small improvement is not statistically significant. Therefore, the support may not influence the electrocatalytic activity of IrO2.