Cs2AgInCl6 double perovskite quantum dots decorated with Ag nanoparticles for photocatalytic CO2 reduction

Abstract

Halide perovskite quantum dots (HP QDs) have been widely used in the field of photocatalysis due to their excellent performance. However, the issues of lead toxicity and instability prevent their process in the photocatalysis application. Herein, the lead-free Cs₂AgInCl₆ perovskite quantum dots (CAIC QDs) are synthesized by the hot-injection method, and CAIC QDs@Ag composites with various Ag loading amounts are self-assembled by adjusting the Cl source in the synthesis process, which is used to improve the CO₂ photoreduction efficiency by using the surface plasmon resonance (SPR) effect of Ag nanoparticles. In addition, the surface ligand density of CAIC QDs@Ag composites is regulated by the purification processing treatment to release the influence of organic ligands on the charge transport performance. It is found that the CAIC QDs@Ag composite with the optimal ligands density possesses fast electron transport and effective carrier separation efficiency, which are crucial for the improvement of the photocatalysis reaction. As a result, the CAIC QDs@Ag-2 composite after purification processing achieves the highest yield of 26.4 μmol g⁻¹ and 28.9 μmol g⁻¹ for CO and CH₄, respectively, during the CO₂ photoreduction process. In addition, there is no significant decline of CO₂ photoreduction performance after the photocatalysis cycling test for 9 h, indicating the good stability of the CAIC QDs@Ag composite in the photocatalysis process.