1. Context

1.1 Dihydrogen, an energy carrier

Dihydrogen has an energy density of 120 MJ · kg ^–1 : this is the highest energy density of all conventional fuels. Consequently, its combustion in an internal combustion engine, or its electrochemical dissociation in a fuel cell, is accompanied by a significant release of energy, in the form of heat and/or electricity. The energy released by these two conversion processes can be reused without any greenhouse gas emissions. These characteristics make hydrogen a highly attractive energy carrier for replacing hydrocarbons.

However, there are still a number of challenges to be overcome before this molecule can be deployed in various industrial sectors. Firstly, the energy density of gaseous...