Novel application of a Z-scheme photocatalyst of Ag3PO4@g-C3N4 for photocatalytic fuel cells

Abstract

A composite of Ag₃PO₄@g-C₃N₄ with the Z-scheme structure was synthesized, and used as the photoanode in a photocatalytic fuel cell (PFC). With the help of the Z-scheme design, both the degradation of tetracycline and the output of maximum power density (P_max) were greatly enhanced in this PFC system. The degradation rate of tetracycline in the Ag₃PO₄@g-C₃N₄ PFC was 2.53 times and 3.65 times that in the PFC systems with the Ag₃PO₄ photoanode and the g-C₃N₄ photoanode, respectively. The P_max of the Ag₃PO₄@g-C₃N₄ PFC was 6.06 μW cm^-2, which was 1.46 times and 90.4 times that of the Ag₃PO₄ PFC (4.16 μW cm^-2) and the g-C₃N₄ PFC (0.067 μW cm^-2), respectively. The possible mechanism was proposed. The Z-scheme photoanode could not only contribute to the separation of photogenerated carriers to achieve a high photocatalytic activity, but also reserve a good redox capacity. Additionally, aeration played an important role on the PFC performance. It was demonstrated that N₂ purging facilitated the electricity generation, while O₂ purging promoted the pollutant degradation.

Keywords: Ag(3)PO(4); Dodecahedron; G-C(3)N(4); Photocatalytic fuel cell; Visible light; Z-scheme photocatalyst.