1. Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Ume(a)University, 5E-901 87 Ume(a), Sweden;2. Department of Physics, Ume(a)University, SE-901 87 Ume(a), Sweden;3. Microelectronics and Materials Physics Laboratories, Department of Electrical Engineering, University of Oulu, P.O.Box 4500, Oulu FI-90014, Finland
Abstract:
Nanosized metal (Pt or Pd)-decorated TiO2 nanofibers (NFs) were synthesized by a wet impregnation method. CdSe quantum dots (QDs) were then anchored onto the metal-decorated TiO2 NFs. The photocatalytic performance of these catalysts was tested for activation and reduction of CO2 under UV-B light. Gas chromatographic analysis indicated the formation of methanol, formic acid, and methyl formate as the primary products. In the absence of CdSe QDs, Pd-decorated TiO2 NFs were found to exhibit enhanced performance compared to Pt-decorated TiO2 NFs for methanol production. However, in the presence of CdSe, Pt-decorated TiO2 NFs exhibited higher selectivity for methanol, typically producing ～90 ppmg?1·h?1 methanol. The CO2 photoreduction mechanism is proposed to take place via a hydrogenation pathway from first principles calculations, which complement the experimental observations.
