Structural and Optical Properties of Ultra-thin g-C3N4 nanotubes based g-C3N4/Ag/Ag2CrO4 ternary composite photocatalyst with Z-scheme carrier transfer mechanism

Ultra-thin g-C3N4 nanotubes with a wall thickness of about 10 nm were prepared by calcining a supramolecular precursor synthesized from cyanuric acid, melamine and urea. After Ag nanoparticles were deposited on the surface of g-C3N4 nanotubes and partially oxidized to Ag2CrO4, a g-C3N4/Ag/Ag2CrO4 ternary nanocomposite was obtained. The structural, optical and electronic properties of the composite were investigated. Compared with pure g-C3N4 nanotubes and g-C3N4 nanotubes decorated with Ag nanoparticles, the photocatalytic performance of the ternary composite is much improved due to its large specific surface area and effective separation efficiency of photo-generated electron-hole pairs. Furthermore, the composite not only promotes the effective separation of photo-generated carriers, but also inhibits the photocorrosion of its Ag2CrO4 component. A Z-scheme photo-generated carrier transfer mechanism with strong redox ability between the components in the g-C3N4/Ag/Ag2CrO4 ternary composite is confirmed by constructing the band structure of the composite. The high photocatalytic degradation performance of organic pollutants after several cycle tests makes it possible to be applied in practice.