Institute of Chemistry and Processes for Energy, Environment and Health, France
Title: Hydrogen production from water using the sun via photocatalytic processes on Au/g-C3N4/TiO2 materials
Biography: Valerie keller
The direct conversion of solar energy through an energy carrier (fuel), storable and usable upon request, appears as an interesting alternative to find environmentally friendly ways to produce energy. Photocatalysis is a promising way to produce hydrogen from renewable energy sources. Indeed, the water dissociation (water-splitting) highlighted by Fujishima and Honda in a photoelectrocatalytic cell opened a promising way to produce hydrogen from light energy. Since, many efforts have focused on the development of the water-dissociation in photoelectro- and photo- catalytic systems. Nowadays, one of the main challenges consist in the elaboration of semiconductor nanometarials able to absorb visible-light wavelengths, to transfer efficiently the photogenerated charges, while keeping high stability of their performances under UV activation. For that purpose, different strategies are studied: Synthesis of semiconductors with narrow band gaps, doping (cationic, anionic, co-doping) approaches of wide bang gap semiconductors, heterojunction formation between wide- and a narrow band gap semiconductors for solar light harvesting, deposition of metal nanoparticles inducing surface plasmon effects, use of different morphologies (1D, 2D, 3D) and assembly of semiconductors. Here, amongst these different approaches, we will focus on the elaboration of Au/gC3N4/TiO2 photocatalysts, in order to optimize the different functions of the composite materials: optimization of the synthesis of C3N4 (under different atmospheres) and TiO2 (influence of the morphology) semiconductors, high quality heterojunction formation, improved Au deposition leading to enhanced electron traps and co-catalyst properties and study of the SPR (Surface Plasmon Resonance) properties induced by Au NPs.