2D Porous graphitic C3N4 nanosheets/Ag3PO4 nanocomposites for enhanced visible-light photocatalytic degradation of 4-chlorophenol

A novel visible-light-activated photocatalyst consisting of porous graphitic C3N4 nanosheets and Ag3PO4 nanoparticles were synthesized through a tunable in situ deposition method. The morphology and microstructure of the C3N4/Ag3PO4 nanocomposites were carefully characterized by scanning electron microscope, TEM, X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectra, and so on. The porous C3N4/Ag3PO4 nanocomposites were featured by the typical platelet-like morphology, with an average crystallite size of about 39 nm. The coexistence of porous graphitic C3N4 nanosheets and Ag3PO4 nanoparticles is confirmed via the XRD and EDX results. Owing to its narrower band gap of Ag3PO4, the nanocomposites displayed a significant redshift of UV-Vis spectral absorption edge together with expanded light absorption in comparison with g-C3N4 nanosheets. The photocatalytic activity of the prepared C3N4/Ag3PO4 nanocomposites is demonstrated by the photodegradation of 4-chlorophenol (4-CP). The C3N4/Ag3PO4 nanocomposites displayed higher photocatalytic activity than pure C3N4 or Ag3PO4, which could be attributed to the interfacial effect of the nanocomposites in inhibiting the unfavorable recombination of photogenerated electrons and holes. Electron spin resonance spin-trap study implied that the generation of hydroxyl radicals plays the key role in the photodegradation of 4-CP by the C3N4/Ag3PO4 nanocomposites under visible light irradiation.