Synchronous synthesis of Cu2O/Cu/rGO@carbon nanomaterials photocatalysts via the sodium alginate hydrogel template method for visible light photocatalytic degradation

A series of Cu2O/Cu/rGO@carbon nanomaterial (Cu2O/Cu/rGO@CN) heterogeneous photocatalysts were successfully synthesized synchronously via a novel sodium alginate hydrogel method. Cu2O nanopartides (similar to 50 nm) were synthesized by calcination under the protection of a nitrogen atmosphere. Cu nanoparticles (similar to 6 nm) inevitably appeared on the surface of Cu2O, thereby forming a Cu2O/Cu heterostructure which is known as a Schottky junction. Graphene oxide (GO) nanosheets were synchronously reduced in situ by sodium alginate during the synthesis process and eventually acted as a 3-D structure with the assistance of the hydrogel skeleton. Because of the 3-D rGO modification, both the adsorption capacity and the photocatalytic activity of Cu2O/Cu/rGO@CN were significantly improved. The rate of p-nitrochlorobenzene (p-NCB) degradation catalyzed by Cu2O/Cu/ rGO@CN was similar to 1.97 x 10(-2) min(-1), which was much higher than that of the degradation catalyzed by Cu2O/Cu@CN (similar to 0.239 x 10(-2) min(-1)). This result could be attributed to the two-stage Cu2O/Cu/rGO heterostructure, which facilitated efficient electron-hole separation. This method has the advantages of nontoxic raw materials, facile synthesis and reduced auxiliary usage, providing a new technique for designing heterogeneous photocatalysts. (C) 2019 Elsevier B.V. All rights reserved.