Photocatalytic reduction of CO2 with H2O over modified TiO2 nanofibers: Understanding the reduction pathway

The photocatalytic performance of nanosized metal (Pt or Pd)-decorated TiO2 nanofibers (NFs) with CdSe quantum dots were tested for activation and reduction of CO2 under UV-B light. The CO2 photoreduction mechanism is proposed to take place via a hydrogenation pathway from first principles calculations. This work was performed in collaboration with the University of Oulu and the Åbo Akademi University, the manuscript is published in the journal of Nano Research.

Anjana Sarkar, Eduardo Gracia-Espino, Thomas Wågberg, Andrey Shchukarev, Melinda Mohl, Anne-Riikka Rautio, Olli Pitkänen, Tiva Sharifi, Krisztian Kordas, Jyri-Pekka Mikkola.
Nano Research, 2016 DOI:10.1007/s12274-016-1087-9

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.