An Efficient, Visible Light Driven, Selective Oxidation of Aromatic Alcohols and Amines with O2 Using BiVO4/g-C3N4 Nanocomposite: A Systematic and Comprehensive Study toward the Development of a Photocatalytic Process

Abstract

In this study, BiVO 4 was prepared by a hydrothermal synthesis route in the presence of sodium dodecyl sulfate using aqueous NH 3 as precipitant. g-C 3 N 4 was prepared by a combustion method using melamine. In order to develop highly efficient photocatalyst, a heterojunction catalyst based on g-C 3 N 4 and BiVO 4 was prepared. Different amounts of BiVO 4 and g-C 3 N 4 were mixed and annealed to obtain heterojunction photocatalysts. FeVO 4 and LaVO 4 were also prepared for the comparative catalytic investigation. Catalysts were characterized by a series of complementary combinations of powder X-ray diffraction, thermogravimetric analysis, elemental analysis, N 2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, temperature-programmed desorption of NH 3 and CO 2, diffuse reflectance ultraviolet visible spectroscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, and photoelectrochemical studies. Catalysts were investigated in the visible light driven oxidation of benzyl alcohol, benzyl amine, and aniline with O 2 . In order to propose the electrons, holes, and radicals mediated reaction pathways, reactions were performed in the presence of an electron/hole/radical scavenger. Further, in order to confirm various products formed during the photocatalytic oxidation of benzyl alcohol, benzyl amine, and aniline, several model reactions were carried out. Based on the results obtained, the reaction mechanism and structure–activity relationship were established.