Role of Graphene Oxide in Ag3PO4/graphene Oxide Composites for Enhanced Visible-light-driven Photocatalytic Ability

The graphene oxide (GO) is fabricated by chemical oxidation or chemical oxidation combined with ultrasonic irradiation (COUI) from graphite. Ag3PO4 particles are anchored on GO by facile ion-exchange method. The as prepared GO and Ag3PO4/GO composites are systematically characterized. The addition of ultrasonic irradiation to the chemical oxidation promotes the oxidation of graphite. Besides epoxide and hydroxyl groups, which are generated in GO during chemical oxidation, epoxide and hydroxyl groups are also formed in GO oxidized by COUI. The valence band (VB) and conduction band (CB) potentials of GO are correspondingly changed. The Ag3PO4 particles are decreased to be smaller size by the stabilization effect of GO and are enwrapped by GO. The photocatalytic ability of prepared samples is evaluated by phenol degradation under visible light irradiation. The removal rates of phenol with Ag3PO4/GO composites are higher than that with Ag3PO4. And the photocatalytic ability of Ag3PO4/GO composite is further enhanced by the modification with GO prepared by the addition of ultrasonic irradiation to the chemical oxidation. This increase can be attributed to collection effects of elevated light absorption ability and increased separation efficiency of the photogenerated charge carriers.