The development of cost-effective green hydrogen-generation systems is one of the most pressing challenges towards the development of a vibrant low-carbon economy. The impact of hydrogen on the UK's roadmap to Net Zero is extensively described in the government's 2021 Hydrogen Strategy and the Ten-Point Plan for a Green Industrial Revolution. The UK aims to develop a 5 GW low-carbon production by 2030. Towards this target, hydrogen production by water electrolysis, green hydrogen, play a central role. Matured water electrolysis technologies such as alkaline (AEC) and polymer electrolyte membrane (PEM) electrolysers are currently being scaled up as energy-storage systems coupled to renewable-energy generation. However, aspects such as hydrogen compression and availability of key raw materials (e.g. Pt and Ir) pose important challenges towards operations at the GW scale. Operating electrolysers at high temperature and pressure, such as in the case of solid oxide electrolysers (SOE), offers substantial advantages with regards to the overall energy balance and hydrogen generation efficiency. However, SOE is an emerging technology which also faces challenges in scalability associated with manufacturing high-quality ceramic membrane systems. SuperH2 is a collaboration between University of Bristol and Supercritical Solutions Ltd, a SME based in London, aiming at the development of dimensionally stable materials for water electrolysis under supercritical conditions. These materials will be key active elements in a highly novel electrolyser design working under flow of supercritical water, leading to the separation of H2 and O2 driven by buoyancy, without the presence of a membrane. This unique technology can utilise waste heat from industrial sites, while generating H2 at pressures above 220 bar. SuperH2 will examine the electrocatalytic activity of Ni based materials, modified with Pt, Fe and Co, towards the hydrogen evolution reaction (HER) in alkaline solutions from standard to supercritical conditions. We will utilise boron-doped diamond (BDD) electrodes as dimensionally stable supports for the metallic active sites. The project will deliver a composition-activity correlation towards HER in alkaline electrolytes at standard and supercritical conditions. At the fundamental level, these studies will uncover how water dissociation dynamics at metallic sites, the key limiting step in HER under alkaline conditions, can be affected by temperature and pressure. These studies will also establish correlations between stability and activity, which is key for formulating electrode material in supercritical water electrolysers.

A thriving, low carbon hydrogen sector is essential for the UK's plans to build back better with a cleaner, greener energy system. Hydrogen has the potential to reduce emissions in some of the highest-emitting and most difficult to decarbonise areas of the economy, which must be transformed rapidly to meet Net Zero targets. To achieve this, large amounts of low carbon hydrogen and alternative liquid fuels will be needed. These must be stored and transported to their point of use. There remain significant research challenges across the whole value chain and researchers, industry and policy makers must work collaboratively and across disciplines to drive forward large-scale implementation of hydrogen and alternative liquid fuels as energy vectors and feedstocks. The flagship UK-HyRES hub will identify, prioritise and deliver solutions to research challenges that must be overcome for widespread adoption of hydrogen and alternative liquid fuels. It will be a focus for the UK research community, both those who are already involved in hydrogen research and those who must be involved in future. The UK-HyRES hub will provide a network and collaboration platform for fundamental research, requiring the combined efforts of scientists, engineers, social scientists and others. The UK-HyRES team will coordinate a national, interdisciplinary programme of research to ensure a pipeline of projects that can deliver commercialisation of hydrogen and alternative liquid fuel technologies that are safe, acceptable, and environmentally, economically and socially sustainable, de-coupling fossil fuels from our energy system and delivering greener energy. We intend that, within its five-year funding window and beyond, UK-HyRES will be recognised internationally as a global centre of excellence and impact in hydrogen and alternative liquid fuel research.