Non-stoichiometric Ag-In-S quantum dots for efficient photocatalytic CO2 reduction: Ag/In molar ratio dependent activity and selectivity

Photocatalytic reduction of CO2 to syngas is a desirable strategy for recycling CO2 into valuable products, meeting energy demands in a sustainable way. Herein, we report the use of non-stoichiometric Ag-In-S quantum dots (QDs) as highly efficient and robust photocatalysts for visible-light-driven photocatalytic reduction of CO2 to syngas at atmospheric pressure and room temperature. The introduction of Co(bpy)32+ (bpy = 202-bipyridine) cocatalyst can promote the conversion of CO2 to CO reaction and meanwhile improve the photo-stability of Ag-In-S QDs. The photocatalytic activity and selectivity of Ag-In-S QDs are strongly dependent on the Ag to In molar ratios, and the optimized sample exhibits the highest CO evolution rate of 9.20 mu mol h(-1) and H-2 evolution rate of 3.13 mu mol h(-1), corresponding to the CO selectivity of 74.61%, outperforming most of the reported QDs based photocatalysts. This work provides a new example of Cd and Pb free QDs photocatalyst for efficient and stable CO2 photoreduction. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

This study demonstrates the use of non-stoichiometric Ag-In-S quantum dots as efficient photocatalysts for visible-light-driven photocatalytic reduction of CO2 to syngas. The addition of a cocatalyst can enhance reaction efficiency and stability, leading to high rates of CO and H2 evolution with improved CO selectivity in the optimized sample.