SiC-Si as a support material for oxygen evolution electrode in PEM steam electrolysers

The need of higher energy efficiency in hydrogen production has promoted the research on improved catalysts for water electrolysis. In this work, a novel supported catalyst for oxygen evolution electrodes was prepared and characterized with different techniques. IrO2 supported on a SiC/Si composite was synthesized following the Adams fusion method. The obtained powder was characterized with different techniques. XRD and Nitrogen adsorption experiments showed the influence of the support particles in the surface properties of the IrO2 particles, mainly affecting the IrO2 particle size. The prepared catalysts were electrochemically characterized by cyclic voltammetry experiments at 25, 80, 120 and 150°C. The results indicate an improvement in catalyst activity with the addition of the support. This was attributed to the mentioned variation in particle size and a different packing of catalyst particles, which could favor the formation of channels and pores between particles, thus increasing the catalyst utilization. Electric conductivity tests were performed on the powder samples, showing a very low conductivity of the support compared to the active phase. The conductivity of the supported catalysts seems to depend strongly on the density of contacts between IrO2 particles, with the support particles disrupting the conduction paths through the powders.