Europium single atom based heterojunction photocatalysts with enhanced visible-light catalytic activity

Abstract

Promoting charge separation is still the main challenge in the rational design of photocatalysts for visible light photocatalytic reduction of CO₂. Based on the unique advantages of the Eu³⁺ single atom and the Type-II heterojunction in the field of photocatalytic reduction, a Eu³⁺ single atom doped CdS/InVO₄ Type-II heterojunction was successfully constructed through the combination of hydrothermal and in situ synthesis. The prepared CdS/InVO₄:Eu³⁺ single atom composite material has excellent photocatalytic CO₂ reduction activity under visible light. The XPS test results show that the In 3d, O 1s, V 2p, and Eu 3d peaks of 10-CdS/IVO:Eu³⁺ move slightly towards a low energy direction, while, the positions of Cd 3d and S 2p peaks are both shifted to the direction of high binding energies, which indicated that the electrons can be transferred from CdS to IVO with the help of Eu³⁺. The CO yield of CdS/InVO₄:Eu³⁺ was 11.02 μmol g⁻¹ h⁻¹, which was almost 2.4 times that of pure InVO₄ and 1.9 times that of pure CdS, and the yield of CH₄ of CdS/InVO₄:Eu³⁺ reached 8.24 μmol g⁻¹ h⁻¹, which was 5.3 times and 10.6 times that of InVO₄ and CdS, respectively. Both the theoretical and experimental results show that the single atom Eu³⁺ can not only modify InVO₄ and activate CO₂ molecules, but can also promote charge separation between the interface and improve the photocatalytic performance. It is expected that the research results of this paper can provide a novel idea for the rational design of rare earth monatomic catalysts.