Semiconductor-based photocatalytic technology, using abundant and renewable sunlight as an induced light source represents an emerging successful technology to solve the global energy and environmental challenges. Considerable efforts have been paid to develop novel photocatalysts with good response to sunlight and high quantum conversion efficiency. In this work, single ZnNCN microparticles have been prepared by the ligand exchange reaction between zinc salt, ammonia and cyanamide. And Ag2NCN/ZnNCN hetero structure has been also fabricated using the same ligand exchange process but mixing the silver salt with zinc salt together. Some means, such as XRD, SEM, infrared spectroscopy (FT-IR) and ultraviolet visible spectrometer (UV-Vis) were used to characterize the samples. The results showed that the single ZnNCN was flower-like particles with wide band gap (Eg=4.71 eV). Compared with single ZnNCN, the Ag2NCN/ZnNCN composite particles presented different morphology with rough surface, and physical interaction was existed between two kinds of metal cyanamide for Ag2NCN/ZnNCN composites. Because of the heterostructure, the light response spectrum for Ag2NCN/ZnNCN composite particles was extended to the visible light region, and the band gap was changed to 2.05 eV. The photocatalytic activity of Ag2NCN/ZnNCN composite particles in the degradation of Rhodamine B under Xenon irradiation was investigated, meanwhile, single ZnNCN and the mixture of Ag2NCN and ZnNCN was also applied in the photocatalysis under same conditions for comparison. The apparently enhanced photocatalytic activity of Ag2NCN/ZnNCN heterostructure was observed, and a first-order kinetic was discussed.
Fund: Supported by National Natural Science Foundation of China (No.21501023) and National Undergraduate Innovation and Entrepreneurship Training Program (No.201610145019)
Fig.1 SEM images of ZnNCN (a), Ag2NCN (b) and Ag2NCN/ZnNCN (c) and EDS of Ag2NCN/ZnNCN composites (d)
Fig.2 XRD spectra (a) and FT-IR spectra (b) of ZnNCN, Ag2NCN and Ag2NCN/ZnNCN particles
Fig.3 UV-Vis diffuse reflectance spectra of ZnNCN, Ag2NCN and Ag2NCN/ZnNCN particles (a), and corresponding curves of (A×hν)2vs hν of ZnNCN (b) and Ag2NCN/ZnNCN (c) particles (A—absorbance, h—Plank constant, ν—frequency)
Fig.4 Photocatalytic kinetics of Rhodamine B by three kinds of photocatalysts (a) and fitting curve of degradation kinetics data of Rhodamine B by Ag2NCN/ZnNCN particles (b) (c—equilibrium concentration of Rhodamine B, t—adsorption time)
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