Thermal effect on the photoelectrochemical performance and interface charge transfer of CuInS2/TiO2 NTs photoelectrode

As a photothermal material, CuInS2 can effectively use the infrared spectrum to trigger the thermal effect and provide the required endothermic energy for the reaction. Here, CuInS2/TiO2 NTs composite photoanode was constructed, and the influence of thermal effect on its photoelectrochemical properties was systematically studied. It was found that CuInS2 nanoparticles could effectively convert light energy into heat energy, which led to the local temperature rise of CuInS2/TiO2 NTs under light irradiation. Furthermore, by regulating the ambient temperature from 20 ℃ to 60 ℃, the photocurrent density and photocurrent efficiency of CuInS2/TiO2 NTs increased significantly because the thermal effect could effectively inhibit the bulk recombination of photogenerated carriers and accelerate the charge transfer. The oxygen bubbles on the surface of CuInS2/TiO2 NTs photoanode had smaller diameter and showed faster desorption. Therefore, the thermal effect was conducive to charge transfer in the interfacial charge transfer kinetics of CuInS2/TiO2 NTs. It suggests that the introduction of thermal effect plays an auxiliary role in improving the photoelectrochemical reaction, and can provide a cheap and competitive method to effectively improve the photochemical performance of the photoanode.