Clean and sustainable hydrogen will have a major impact in the future of several sectors of our economy - from industrial processes (e.g. steel and concrete manufacturing), domestic and industrial heating, to the transportation sector (e.g. fuel cells and combustion engines), hydrogen offers many pathways to decarbonisation. This has been clearly articulated recently in the UK Government's Hydrogen Strategy. However, to enable hydrogen to fulfil its potential, it must be produced by renewable power, without carbon-emissions. Splitting water into hydrogen and oxygen with electricity (electrolysis) is one of the most promising technologies to meet this challenge. Indeed, commercialised electrolysers exist today that generate "green" hydrogen at industrially relevant scales. However, to date, 96% of hydrogen is produced from fossil fuel derived processes resulting in carbon-emissions. While a portfolio of electrolyser technologies will likely play important roles in the long term, proton exchange membrane electrolysers (PEM-ELs) are widely anticipated to provide the base capacity in the short and medium term. Despite this expectation, the high cost of green hydrogen from PEM-EL is a major barrier. PEM-ELs today require precious and scarce iridium and platinum-based catalysts. Indeed, technoeconomic analyses show that when manufactured at scale, the PEM-EL stack is the most expensive component of the electrolyser, and the anode electrodes (iridium catalyst and transport layers) will account for the majority of the stack cost. Diversification of catalyst composition (i.e. to move away from pure iridium catalysts) thus, represents a substantial opportunity that could enable significant growth in green hydrogen generation using PEM-Els.

This proposal offers a novel and unified strategy to develop synthetic methods and utilise advanced materials characterisations to feed-forward into the design of reduced iridium-content catalysts. We will explore our electrocatalysts through a translational approach, from "model system" thin films, to nanopowdered studies and commercially relevant testing, providing insight into which properties (conductivity, intrinsic activity, durability) dictate and control catalyst performance across these different testing beds. Furthermore, our synthesis methods, including co-sputtering from multi-magnetron systems will enable precision and great flexibility in catalyst composition. Working with our industrial partner, Johnson Matthey, the most active nanopowder catalysts will be benchmarked against commercial materials using industrial testing protocols. Throughout the project, we will leverage an array of advanced materials characterisation techniques to correlate structural and chemical properties to the catalyst performance, mimicking the operating conditions within a working electrolyser.

In summary, the proposed work herein will implement catalysts with nanometer precision, uncovering design strategies and characterising catalysts under operating conditions and therefore accelerating the development of cost-effective catalysts for sustainable hydrogen production.