This novel material photocatalyzes the production of hydrogen from water and light
By anchoring molybdenum clusters onto a sheet of graphene, researchers have created a material that photocatalyzes the splitting of water into hydrogen and oxygen, pointing the way toward new ways to produce hydrogen fuel (Inorg. Chem. 2019, DOI: 10.1021/acs.inorgchem.9b02529).
Water is a plentiful raw material that could supply hydrogen fuel carbon-free if the conversion from one to the other could be done efficiently and cheaply. The right photocatalyst would absorb sunlight, excite electrons in the material to a higher energy state, and then transfer those electrons to the surface of the catalyst, where the water-splitting reaction takes place.
Transition-metal clusters do an excellent job of emitting light, which suggests they have the right electronic properties for catalysis. And graphene can easily deliver excited electrons back to the metal clusters. Previous work, though, had shown that covalent grafting of metal clusters onto sheets of graphene oxide creates defects in the graphene, changing its electrical conductivity and undermining the clusters’ ability to perform catalytic reactions.