Analysis of synergistic effect between graphene and octahedral cuprous oxide in cuprous oxide-graphene composites and their photocatalytic application

Abstract

The octahedral cuprous oxide (Cu2O) supported by reduced graphene oxide composites (Cu2O-RGO) are compounded via a gentle one-pot in situ method. The reduction of GO and the growth of octahedral Cu2O particles simultaneously occur with the Cu2O particles depositing on RGO nanosheets uniformly. The enhanced photocatalytic properties are appraised by decomposition of methyl orange under visible light irradiation. Compared with the pure octahedral Cu2O particles and RGO, the as-prepared composites degrade methyl orange completely within 50 min with apparent rate constant at 82.88 × 10−3 min−1, ten times of the pure octahedral Cu2O particles and twenty-seven times of RGO. Scavengers are also introduced to investigate the photocatalytic mechanism which turns out that h+ and O2¯ radicals are the main active species in the photocatalysis process. The synergistic effect between RGO and octahedral Cu2O particles in the photocatalysis process is systematacially analyzed for the first time. Carrier generation occurs on the Cu2O particle, and electron is collected and transported by graphene here to prolong the charge carriers' lifetime, leading to strong absorbance in visible light region, instant carrier separation, and fast charge transfer. Thus the efficiency of visible-light-driven photocatalysis is greatly enhanced.