AgInS₂ nanoparticles modified TiO₂ nanotube array electrodes: Ultrasonic-assisted SILAR preparation and mechanism of enhanced photoelectrocatalytic activity

The AgInS₂/TiO₂ nanotube array electrodes were successfully prepared by depositing AgInS₂ nanoparticles onto well-aligned anodized TiO₂ NTs via an ultrasonic-assisted successive ionic layer absorption and reaction (SILAR) method. The microscopic morphology, composition and interfacial structure were well characterized with field-emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectra and transmission electron microscopy. The optical property was investigated by UV–vis diffusion reflection spectra. Photoluminescence investigation demonstrated that the constructed heterojunctions reduced the recombination rate of photoinduced charges in the composite. Furthermore, transient photovoltage technique revealed that AgInS₂/TiO₂ NTs electrode had high separation efficiency of photoinduced electrons and holes. Finally, the composite electrode was tested by degradation of Norfloxacin (NOR) under simulated solar irradiation. Electron spinning resonance study indicated that O₂^•− species played an essential role for efficient NOR photodegradation. The higher photoelectrochemical performance of AgInS₂/TiO₂ NTs electrode could be attributed to the finely deposited AgInS₂ nanoparticles, which improved the light adsorption and facilitated the charge transfer.