Synthesis of three-component Cu2O/ZnO/Ag nanocrystal heterogeneous photocatalysts with high reactivity and stability for dye reduction

Abstract

Semiconductor nanocrystals are widely used as photocatalysts for the degradation of organic dye molecules due to their strong electron transfer ability and high catalytic reactivity. However, as a photocatalyst with excellent performance, semiconductor nanocrystals still have some disadvantages, such as aggregation, photocorrosion during the reactions, and loss during recycling that need to be addressed. In response to these problems, it is necessary to improve the using efficiency of “active charges” of the photocatalysts and their stability in the recycling process, which can be achieved by transferring the unreacted “active charges” to other active materials and fixing the photocatalysts in the polymer matrix. Here, we designed nanocrystals with three components, Cu₂O–ZnO–AgNC (silver nanocube), as photocatalysts with high stability and high reactivity for the degradation of Congo red molecules under irradiation in the visible light range. The high reactivity of Cu₂O–ZnO–AgNC as a photocatalyst can be attributed to the generation of “active charges”, hot electrons from AgNC, and excited electron–hole pairs from Cu₂O under visible light irradiation. Moreover, the photocorrosion of Cu₂O can be suppressed by transferring the unreacted “active charges” to ZnO and the photocatalytic performance can be further improved. These results enable the design and synthesis of catalysts or photocatalysts with high catalytic performance for various reduction reactions.