Materials for photocatalysis
Stéphane Jobic (DR), Xavier Rocquefelte (MCF, then Pr. à l'Univ. de Rennes 1 since Sept. 2014)
Our expertise in the field of materials with photoinduced properties (luminescence, photovoltaic, photochromes) naturally led us to have a look on semiconductors that can exhibit photocatalytic properties. Our objective was to define the ingredients necessary to obtain a semiconductor with good performance for photocatalysis in the visible field. To this end, we first studied the properties of excitons (electron-hole pairs) via a Bethe Salpeter approach for two allotropic varieties of BiVO4, the scheelite variety presenting a photocatalytic activity much greater than the dreyerite one. We then developed an approach to determine ab initio the energy positions, on an absolute scale, of the valence band and conduction band to predict the capability of a solid material to oxidize or reduce specific species. Indeed, to be a good candidate for photocatalysis in the visible domain, a solid material must absorb the visible light, but also have an appropriate position in energy of its valence and conduction bands. This activity goes hand in hand with the development of new plasmon photocatalysts described in the section "Photoactivable hybrid materials".
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| Figure. Energy position of the top of the valence band (blue) and the bottom of the conduction band (red) for a range of 11 semiconductors. The calculated values are derived from the method we have developed based on DFT calculations using the HSE hybrid functional. |
Involved people
Current: Stéphane Jobic (DR), Xavier Rocquefelte (MCF, puis Pr. à l'Univ. de Rennes 1 depuis Sept. 2014)
Past: Tilak Das
Collaborations
Institut des Sciences Chimiques de Rennes
Thesis
Theoretical study of the electronic and optical properties of photocatalytic inorganic materials, Tilak Das, 2012,