Preparation of g-C3N4(Ag)/Gr/TiO2 Z-scheme photocatalyst with enhanced reduction property and the efficient degradation of rhodamine B

Abstract In this work, to enhance the mineralization of the organic dyes, the g-C3N4(Ag)/Gr/TiO2 Z-scheme photocatalyst was successfully prepared by hydrothermal method. The XRD and XPS results showed that the nanocomposite was constructed. The SEM and EDS results showed that the morphology of g-C3N4(Ag)/Gr/TiO2 was that TiO2 nanoparticles distributed on the surface of the Gr/g-C3N4 layers. The photocatalytic performance of the prepared samples was evaluated by the photocatalytic degradation and mineralization of RhB under visible light irradiation. The degradation efficiency of RhB on g-C3N4(Ag)/Gr/TiO2 reached 99.7% within 2 h, and the kinetic rate (0.0431 min-1) was 7.1, 7.1, 2.2, 2.0 and 1.3 times higher than those of g-C3N4, TiO2, g-C3N4(Ag)/Gr, g-C3N4/TiO2, and g-C3N4/Gr/TiO2, respectively. The total organic carbon (TOC) removal results showed that the mineralization efficiency of RhB on this composite was as high as 74.5% after 2 h of reaction time. During the photocatalytic process, it was speculated that Gr acted as the electron transporter between TiO2 and g-C3N4, which reduced the recombination efficiency of photo-generated charge carriers, and silver clusters acted as an electron reservoir to accelerate the reduction reaction of photo-generated electrons on the g-C3N4 conduction band, and further improved the photocatalytic performance.