Selective oxidation of benzyl alcohols at ambient conditions in the presence of C3N4 photocatalysts derived from the melamine, cyanuric acid and MFe2O4 (M = Cu, Zn and Ni)
摘要
In this research, magnetic photocatalysts were used to oxidize benzyl alcohols. First, we synthesized graphene carbon nitride using melamine and cyanuric acid precursors (g-C3N4-MCy). Then, it was magnetized using the structures of spinel ferrites (MFe2O4, M = Zn, Cu, and Ni). The prepared samples were characterized by X-ray diffraction (XRD), optical electron microscope (TEM), Fourier transform infrared spectrometer (FTIR), field electron microscope (SEM), spectrum absorption (UV–Vis), determination of specific surface area (SSA) and vibrating sample magnetometer (VSM). TEM and SEM images have shown that the structure of carbon nitride graphene is synthesized as layers and ferrite nanoparticles are unevenly distributed on the surface of the layers. The band gap for g-C3N4-MCy, NiFe2O4/g-C3N4-MCy, CuFe2O4/g-C3N4-MCy and ZnFe2O4/g-C3N4-MCy was obtained as 2.55, 2.2, 1.95 and 2.4 eV, respectively. The study examined the photoactivity of the materials in comparison to the partial oxidation of four substituted benzyl alcohols. The kind and location of substituents in the aromatic molecule affected the conversion and selectivity to the matching aldehyde. Benzyl alcohol conversion and selectivity for benzaldehyde were significantly high; the high photocatalytic performance of ZnFe2O4/g-C3N4-MCy compared to other synthesized nanocatalysts indicates the importance of surface area and energy gap for photocatalytic activity. The oxidation of benzyl alcohol in the presence of nanocomposites with different ferrite types revealed very little photocatalytic activity in the CuFe2O4/g-C3N4-MCy magnetic nanocatalyst.