Effect of transition metal oxide cocatalyst on the photocatalytic activity of Ag loaded CaTiO₃ for CO₂ reduction with water and water splitting

Abstract

Various dual cocatalysts consisting of Ag and transition metal oxide (TMOx) were loaded on a CaTiO₃ (CTO) photocatalyst by different loading methods and examined for the photocatalytic CO₂ reduction with water as an electron donor. Compared to the results provided with the single Ag cocatalyst, the dual cocatalyst loaded CTO photocatalyst exhibited a similar or less CO evolution rate and higher H₂ production, meaning that these photocatalyst showed photocatalytic activity for both CO₂ reduction and water splitting. Dual cocatalysts of Ag and TMOx loaded by a photodeposition gave higher CO production rate than those loaded by an impregnation method. The CTO photocatalysts with a single TMOx cocatalyst showed higher activities in both H₂ evolution and O₂ evolution test than the bare CTO and dual cocatalyst loaded CTO photocatalysts, indicating that the photocatalytic activity for water splitting is suppressed by the Ag cocatalyst but improved by the TMOx.