Hydrogen has the potential to be a zero-carbon fuel source which produces just heat and water when burned or used in fuel cells. This makes it a highly attractive alternative to fossil fuels in heating and transport. A pillar of the UK government’s decarbonisation plan is a huge expansion of hydrogen to 5GW capacity by 2030.

As hydrogen is currently much more expensive to produce than the fuels it could replace, the government is considering providing subsidies to bridge the gap, controversially supporting both green and blue hydrogen (the latter of which can be more polluting than coal). While blue hydrogen is produced from natural gas, green hydrogen is produced by splitting water via electrolysis into hydrogen and oxygen. While green hydrogen is the preferred option given its potential to produce no carbon overall, the process is not yet efficient enough for scaling up.

Typically, scientists have used precious metal catalysts, such as platinum, to...