Valence band engineering of oxidation materials for cheap and sustainable solar fuel production

Given the need to reduce our greenhouse gas emissions and our dependence on fossil fuels, there is a great interest in the development of solar fuels and especially solar H2. However, the production cost of solar H2 is still not yet competitive. Current strategies rely on converting water into H2 and O2, a low-value-added molecule. This is because process feasibility was based on the reduction half-reaction, with the oxidation half-reaction being secondary. In OMATSOLFUEL, the focus is shifted instead to the oxidation half-reaction. I will develop routes for the photoconversion of model glucose reactive mixtures and rich-glucose industrial mixtures. They are cheap, renewable, and could help micro industries become self-sufficient in fuels and energy. Instead of simply generating H2 and O2, the glucose will be photocatalytically converted into high-value-added molecules (e.g. arabinose or erythrose) and H2. These molecules would be highly interesting for plummeting the cost of solar H2 and replacing molecules produced by the petrochemical industry. To reach this objective I will design efficient and selective photocatalysts based on oxynitrides and novel chalcogenides structures. The main efforts will be on the electronic structure engineering by adjusting the S 3p, N 2p, O 2p, and metallic d orbitals to shift the valence band maximum and the oxidation potential of the photogenerated holes closer to the targeted glucose oxidation potentials. Powders and thin films will be synthesized by soft route methods and chemical or physical vapor deposition methods. The resulting morphology, structural and electronic properties will be characterized with the well-equipped platform of the Institut des Matériaux de Nantes (IMN), and in particular with photoelectron spectroscopy.