Morphology and structure of lead-free CuSb-based double perovskites for photocatalytic CO2 reduction

Abstract

Lead-free halide double perovskites (DPs) have attracted great attention due to their stability, nontoxicity, and good photophysical properties. Herein, environmentally friendly small-bandgap Cs2CuSbCl6 and Cs4CuSb2Cl12 DPs microcrystals (MCs) are prepared via a solvent synthesis technique. This study also reports a bottom-up synthetic protocol for obtaining evenly distributed Cs2CuSbCl6 and Cs4CuSb2Cl12 quantum dots (QDs) utilizing a modified hot injection approach. These MCs and QDs have strong absorption throughout the visible region, indicating that they could be promising light-absorbing materials as sunlight-driven photocatalysts. For the first time, the efficient sunlight-driven photocatalytic CO2 reduction activity of these Pb-free “green” MCs and QDs has been revealed, and a product yield of 307 μmol g−1 and an electron consumption of 1053 μmol g−1 are achieved by the Cs4CuSb2Cl12 QDs under 3 h irradiation. Our results highlight the potential of this family of materials for photocatalytic applications.