A novel synthesis method for Ag/g-C3N4 nanocomposite and mechanism of enhanced visible-light photocatalytic activity

A novel synthesis approach toward Ag/g-C3N4 composite photocatalyst is reported. First, g-C3N4 nanoflakes (CNNs) were fabricated by thermal polymerization of melamine precursor combined with gas bubble exfoliation method. Second, Ag nanoparticles were homogeneously dispersed on CNNs by photo-reduction method to assemble Ag/CNNs nanocomposites. The structure of Ag/CNNs nanocomposites was verified by SEM, EDS, TEM, FTIR and XRD. The photocatalytic properties of Ag/CNNs nanocomposites were verified by degradation of Rhodamine B (RhB) under visible light irradiation. The increase of photocatalytic activity of Ag/CNNs nanocomposites was mainly due to the Schottky barrier between Ag and CNNs and the local surface plasmonic resonance (LSPR) effect of Ag NPs, which was conducive to improving the separation and transportation efficiency of photogenerated electrons-holes as well as the absorption of visible light, reducing recombination of free charges. Thus, the Ag/CNNs nanocomposites would show excellent photocatalytic activity in organic waste water treatment.