Enhanced photocatalytic performance of g-C3N4-BiVO4-Ag heterojunction induced by interfacial electric fields and Schottky junction

In this work, g-C3N4-BiVO4-Ag heterojunction was prepared via two-step photo-deposition method. The Ag particles were selectively deposited on the BiVO4(010) facet, while the negatively charged g-C3N4 was selectively deposited on BiVO4(110) facet using NaIO3 as electron trapping agent. The charge separation of g-C3N4-BiVO4-Ag heterojunction was accelerated due to the synergy of the electrostatic attraction between g-C3N4 and BiVO4(110), and the formation of Schottky junction between Ag and BiVO4(010). Moreover, g-C3N4-BiVO4-Ag heterojunction showed enhanced light absorption due to the SPR effect of plasma Ag. At the same time, plasma Ag could generate high-energy hot electrons to reduce O2 molecule to •O2- radical, which could further degraded organic pollutants. Under visible light irradiation, the degradation rates of the optimal heterojunction to RhB, MB and CIP were 0.00882, 0.01507 and 0.001030.00103 min-1, respectively, which were 5.38, 7.81 and 2.02 times higher than that of BiVO4. The enhanced photocatalytic activity of g-C3N4-BiVO4-Ag heterojunction was attributed to the combined effect of interfacial electrostatic electric field between g-C3N4 and BiVO4(110), the built-in electric fields of surface heterojunction and Schottky junction between BiVO4(010) and Ag, and the SPR effect of Ag.