Electrochemical synthesis of p-Cu 2 O/n-TiO 2 heterojunction electrode with enhanced photoelectrocatalytic activity

Abstract A uniform p-Cu 2 O/n-TiO 2 heterojunction electrode was synthesized using electrochemical anodization and pulse electrodeposition. The nucleation and growth of Cu 2 O nanoparticles under pulse potential were investigated and controlled. Energy-dispersive X-ray spectroscopy analysis showed that Cu 2 O nanoparticles (NPs) were uniformly dispersed on the TiO 2 nanotube (TiO 2 NT) surface. X-ray photoelectron spectroscopy and X-ray diffraction analyses indicated the formation of Cu 2 O. The electrodeposition of Cu 2 O on the TiO 2 NT surface enhanced visible light response. The current–voltage curve of the Cu 2 O/TiO 2 electrode revealed the formation of the Cu 2 O/TiO 2 p–n heterojunction. The Cu 2 O/TiO 2 electrode exhibited reduced charge transfer resistance and enhanced charge separation, as indicated by the photoluminescence emission spectra, transient photocurrent response, and photovoltage measurements. The uniform Cu 2 O/TiO 2 heterojunction electrode exhibited enhanced photoelectrocatalytic (PEC) activity toward the degradation of chloramphenicol (CAP) compared with the pristine TiO 2 NT electrode. The Cu 2 O/TiO 2 electrode under electrodeposition cycles of 400 displayed the highest PEC activity. The enhanced activity is due to the synergistic effect between the uniform p-Cu 2 O/n-TiO 2 heterojunction and the small bias potential. The radical species that play a major role in the PEC degradation of CAP are •OH radicals. A possible PEC mechanism of the uniform Cu 2 O/TiO 2 heterojunction electrode was proposed.