CO₂ photoreduction into fuels has the potential to reduce future dependence on fossil fuels. This work has examined the effects of metal ion doping on the properties and performance of TiO₂ for CO₂ reduction in different photoreactor configurations. Metal (Pd/Rh, Ni, Cu, V, Cr and Co) doped TiO₂ photcatalysts synthesized by the sol-gel method were suspended or immobilized onto monoliths threaded with optical fibers or quartz plates. Doping with Cu, V and Cr facilitated anatase to rutile phase transformation, while Ni and Co doping inhibited transformation to rutile. All the metal atoms were found to be replacing some of the Ti atoms in the cystal lattice of TiO₂ during synthesis, thus causing a shift to longer wavelengths. Metal doping can considerably enhance the photocatalytic activity of TiO₂ for CO₂ reduction to fuels under UV or visible light irradiation when H₂O was used as a reductant. The activities of the best photocatalysts (lwt%Cu-TiO₂ and lwt%Co-TiO₂) were 67 times higher than pure TiO₂. More importantly, the conversion rate, 79.95μmol/g<sub>cat</sub>h achieved using the quartz plate reactor was near one order of magnitude higher than other reactor configurations due to better accessibility of the catalytic surface to photons and the reactants during photocatalytic reaction.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:656283 |
| Date | January 2014 |
| Creators | Ola, Oluwafunmilola |
| Contributors | Maroto-Valer, Mercedes |
| Publisher | Heriot-Watt University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10399/2820 |
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