Effects of surfactant and reaction time on the formation and photocatalytic performance of Cu2S thin films grown in situ on Cu foil by hydrothermal method

Cu2S thin films were successfully grown in situ on Cu foil by an easy hydrothermal method. The effects of surfactant and reaction time on the formation of the Cu2S films were studied by X-ray diffraction, field-emission scanning electron microscopy and ABIOS profilometry. Results showed that the thin films consisted of nanoparticles, and their crystallization and surface roughness depended on the structures of surfactants and reaction time. Photocatalytic studies indicated that the film obtained at 1 h by the EDTA-2Na surfactant exhibited a good methylene blue degradation rate of 83.7%, and higher values of 89.2% and 90% were obtained with increased reaction time to 3 and 4 h. Even the decomposition rate remained at high (82%) after reuse. This good catalytic performance can be attributed to the heterojunction formed between Cu and Cu2S, the special surface from the reaction between [Cu-EDTA]- ion and S2−, and the further crystal orientation with prolonged reaction time.