Heterostructured nanocomposite tin phthalocyanine@mesoporous ceria (SnPc@CeO2) for photoreduction of CO2 in visible light

Abstract

Heterostructured tin phthalocyanine supported to mesoporous ceria was synthesized and used a photocatalyst for CO₂ reduction under visible light. The photoreduction CO₂ activities of the heterostructures were investigated in the presence of triethylamine as sacrificial agent. The developed photocatalyst exhibited high catalytic activity for photoreduction of CO₂ and after 24 hours of visible light irradiation 2342 μmol g⁻¹ cat of methanol (ϕ_MeOH = 0.0223 or 2.23%) and 840 μmol g⁻¹ cat of CO (ϕ_CO = 0.0026 or 0.26%) were obtained as the major reaction products. The methanol formation rate (R_MeOH) and CO formation rate (R_CO) was found to be 97.5 μmol h⁻¹ g⁻¹ cat and 35.0 μmol h⁻¹ g⁻¹ cat respectively. While under the identical experimental conditions mesoporous ceria (meso-CeO₂) gave only 316 μmol g⁻¹ cat of methanol (ϕ_MeOH = 0.003 or 0.30%) and 126 μmol g⁻¹ cat CO (ϕ_CO = 0.0004 or 0.04%) with product formation rate R_MeOH = 13.2 μmol h⁻¹ g⁻¹ cat and R_CO = 5.3 μmol h⁻¹ g⁻¹ cat. Furthermore, the recovered catalyst showed consistent catalytic activity for at least five runs without any significant loss in product yields.