Dr Yagya Regmi from Manchester Metropolitan University explains how his group is exploring platinum coated titanium dioxide as supports for iridium catalysts to help reduce the amount of iridium in water electrolysers and lower cost of hydrogen from electrolysis.
Reducing the amount of iridium in water electrolysers without compromising performance is essential to lower cost of hydrogen from electrolysis. One of the pathways used in catalysis is to utilise high surface area supports. In this project, we are exploring platinum coated titanium dioxide as supports for iridium catalysts. Platinum is necessary to improve conductivity of the support motifs. Our strategy is to rapidly test plethora of supported catalysts in a half-cell configuration using rotating disk electrodes. Only those catalysts that show promising activity and durability in half-cell are then integrated into the electrolyser. This approach is economic and efficient since integrating catalysts into membrane electrode assemblies and running electrolyser tests are resource and time intensive. However, there are challenges associated with replicating activity and durability from half-cell to device performance. Thus, we also explore methodologies and strategies to optimise our half-cell investigations to mimic full device conditions more closely. During this UK Catalysis Hub funded project, we have demonstrated that our strategy to engineer iridium catalysts has led to greater than 50% reduction in iridium content necessary in water electrolysers. And yet, our devices show performance and durability comparable to state-of-the-art technology.