Photoreduction of carbon dioxide in the presence of H₂, H₂O and CH₄ over TiO₂ and ZnO photocatalysts

In this study, efficiency of the prepared photocatalysts (TiO₂ and ZnO) on stainless steel mesh network was examined for photoreduction of CO₂ gas. The experiments were performed under direct UV irradiation in a self-designed batch reactor. UV-visible spectra and XRD pattern showed that crystalline structure of the particles did not change in calcinations process. Also, SEM images indicated that semiconductors were well coated on the surface of the mesh. Conversion results showed that photoreduction of CO₂ in the presence of TiO₂ photocatalyst with H₂O reductant had highest conversion. However, the best conversion efficiency for ZnO was achieved in the presence of CH₄ molecules. The conversion products in the presence of CH₄ as reductant can be formate and acetate derivatives, whereas the conversion products in the presence of H₂ can be assigned to the production of methane and formic derivatives.