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

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 H-2 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 H-2 evolution and O-2 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.

Automated summary

Dual cocatalysts consisting of Ag and transition metal oxide loaded on a CTO photocatalyst showed higher CO production rate and improved H2 evolution rate, indicating photocatalytic activity for both CO2 reduction and water splitting. Additionally, CTO photocatalysts with a single TMOx cocatalyst exhibited higher activities in H2 evolution and O2 evolution tests, suggesting an enhancement in water splitting photocatalytic activity by TMOx. On the other hand, the photocatalytic activity for water splitting was suppressed by the Ag cocatalyst.