Preparation, photocatalytic properties and mechanism of Fe or N-doped Ag/ZnO nanocomposites

Fe or N-doped Ag/ZnO nanocomposites were synthesized by the dual-step liquid deposition method and one-step liquid deposition combined with plasma nitriding. The as-synthesized nanocomposites were characterized by transmission electron microcopy, high-resolution transmission electron microcopy, X-ray diffraction and X-ray photoelectron spectroscopy. In addition, the photocatalytic properties of Fe or N-doped Ag/ZnO nanocomposites were evaluated by the degradation of methyl orange (MO) under ultraviolet light irradiation using our self-made photocatalytic apparatus. Results showed that Fe or N-doped Ag/ZnO nanocomposites exhibited superior photocatalytic properties compared to the undoped Ag/ZnO nanocomposites. The concentration of ferric sulfate solution and doping ratio of n(Fe): n(ZnO) played an important role in improving photocatalytic properties of Fe-doped Ag/ZnO nanocomposites and the optimized concentration and doping ratio were determined to be 0.134 M and 5%, respectively. Moreover, the plasma nitriding time also played an important role and the optimal plasma nitriding time was 30 min. The enhanced photoactivity mechanism for Fe or N-doped Ag/ZnO nanocomposites was adequately discussed.