Study of photoreduction of CO2 on yttrium and copper co-doped TiO2 nanoparticles

Yttrium and copper co-doped TiO₂ catalysts were prepared by sol-gel method. The photocatalysts were characterized by means of XRD. By co-doping of Y³⁺ and Cu²⁺ not only could restrain the growth in size and aggregation of the nanoparticles, but also could effectively inhibit phase transformation from anatase phase to rutile. The reduction of CO₂ showed that the nano Y-Cu/TiO₂ obtained obvious photocatalytic reduction activity compared with bare TiO₂. When the addition of yttrium to TiO₂ reached 0.1wt.%, it got the highest activity, producing 126.60μmol/g-cat. of formaldehyde during 6 h reaction under the irradiation of 365nm UV light. However, the reduction efficiency of CO₂ on Y-Cu/TiO₂ was lower compared with Cu/TiO₂ and Y/TiO₂ catalysts because of resistance effects. Mechanism of CO₂ photocatalytic reduction on Y-Cu/TiO₂ catalyst was proposed.