Enhanced Visible-Light Photoactivities of Perovskite-Type LaFeO₃ Nanocrystals by Simultaneously Doping Er³⁺ and Coupling MgO for CO₂ Reduction

The use of solar energy to convert CO₂ into chemical fuels not only can create renewable energy but also can alleviate the greenhouse effect. In this work, MgO/LaFeO₃ : Er³⁺ composites were prepared, and their photocatalytic CO₂ reduction capability was tested under visible-light irradiation. The MgO/LaFeO₃ : Er³⁺ composites displayed improved charge carrier separation efficiency, higher CO₂ adsorption capacity, and increased photoactivities for photocatalytic CO₂ reduction to CO and CH₄ (71.52 μmol g⁻¹ h⁻¹ and 5.54 μmol g⁻¹ h⁻¹, respectively). As a comparison, the production rates of CO and CH₄ are 29.36 μmol g⁻¹ h⁻¹ (CO) and 4.13 μmol g⁻¹ h⁻¹, respectively for pure LaFeO₃. The enhanced photoactivities are attributed to the increased electron-hole separation rate resulting from the Er³⁺ doping and improved CO₂ adsorption capacity by MgO coupling. This work thus identifies a novel approach towards highly efficient photocatalysts for CO₂ reduction.