One-pot synthesis of CdS nanoparticles with surface-phase junctions to catalyze the photo-reduction of CO2 into CO and CH4 selectively

Abstract

Without any external template & surfactant, CdS nanoparticles (NPs) with surface-phase junctions were synthesized directly from CdCl2 and the CS2-storage material (CS2SM) with a simple one-pot strategy, in which only stirring was needed. Under visible light irradiation, the as-synthesized CdS NPs could selectively catalyze the reduction of CO2 to produce CO and CH4 sustainably with a perfect catalyst stability even after 33 h. At 4 °C and the optical power density of 370 mW/cm2, the as-synthesized CdS NPs from 0.5 g CS2SM exhibited 195.41 μmol/gcat CH4 generation capacity and the 9.01 μmol·gcat−1·h−1 maximum average yield, in which the generation ratio of CH4/CO was at 8:2; and the as-synthesized CdS NPs from 2.0 g CS2SM exhibited 119.95 μmol/gcat CO generation capacity and the 3.75 μmol·gcat−1·h−1 maximum average yield, in which the generation ratio of CH4/CO was at 1:3. The research results indicated that CdS NPs with higher hexagonal content and smaller particle size is more active in CO2 photoreduction, which may be due to the low potential CdS NPs surface phase junction reducing the recombination rate of electron hole pairs and improving photocatalytic activity. The simple preparation of CdS NPs and their further photocatalytic CO2 reduction provide a green and sustainable foundation for the application of sulfide photocatalysts.