Photoelectrochemical oxidation of ibuprofen via Cu2O-doped TiO2 nanotube arrays

Abstract A p–n junction based Cu 2 O-doped TiO 2 nanotube arrays (Cu 2 O-TNAs) were synthesized and used as a working anode in a photoelectrochemical (PEC) system. The results revealed that the Cu 2 O-TNAs were dominated by the anatase phase and responded significantly to visible light. XPS analyses indicated that with an amount of 24.79% Cu doping into the structure, the band gap of Cu 2 O-TNAs was greatly reduced. SEM images revealed that the supported TiO 2 nanotubes had diameters of approximately 80 nm and lengths of about 2.63 μm. Upon doping with Cu 2 O, the TiO 2 nanotubes maintained their structural integrity, exhibiting no significant morphological change, favoring PEC applications. Under illumination, the photocurrent from Cu 2 O/TNAs was 2.4 times larger than that from TNAs, implying that doping with Cu 2 O significantly improved electron mobility by reducing the rate of recombination of electron-hole pairs. The EIS and Bode plot revealed that the estimated electron lifetimes, τ el , of TNAs and Cu 2 O/TNAs were 6.91 and 26.26 ms, respectively. The efficiencies of degradation of Ibuprofen by photoelectrochemical, photocatalytic (PC), electrochemical (EC) and photolytic (P) methods were measured.