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.