Photoreactivity and Mechanism of g-C3N4 and Ag Co-Modified Bi2WO6 Microsphere under Visible Light Irradiation

In this study, C3N4@Ag-Bi2WO6 with flower-like architecture was successfully prepared through a facile process. The C3N4@Ag-Bi2WO6 particles with 2–4 μm diameters present remarkable enhanced visible light absorption and electron–hole separation efficiency. Compared with Bi2WO6, Ag-Bi2WO6, and C3N4@Bi2WO6 systems, the C3N4@Ag-Bi2WO6 system exhibits optimal photocatalytic activities in both the degradation of RhB and hydrogen production out of water under visible light irradiation. We propose that these results are attributed to the synergy effects of Ag, g-C3N4, and Bi2WO6 nanophase structures in the C3N4@Ag-Bi2WO6 composites, which results in a fast electron–hole separation and slow charge recombination by a Z-scheme mechanism and ultimately in a higher photocatalytic activity.