Enhanced photoelectrocatalytic performance of ZnIn₂S₄ modified TiO₂ nanotube array toward methylene blue

Environmental pollution caused by organic pollutants has been attracted more and more attention by the researchers. In this paper, ZnIn₂S₄ modified TiO₂ nanotube array (ZnIn₂S₄/TiO₂) composite electrodes are prepared by loading chalcogenide semiconductor material ZnIn₂S₄ on the surface of TiO₂ nanotube array (TiO₂ NTA) for the degradation of methylene blue (MB). The physicochemical properties of ZnIn₂S₄/TiO₂ composite electrodes are analyzed by X-ray photoelectron spectroscopy, X-ray diffraction, photoluminescence spectroscopy and so on. The photoelectrocatalytic degradation rate of ZnIn₂S₄/TiO₂ composite electrode with the concentration of ZnIn₂S₄ as 0.5 mmol/L (ZISTO-2) reaches 93.3% under the bias voltage of 0.7 V and simulated sunlight irradiation for 180 min against MB, which is 22.44% higher than that of pure TiO₂ NTA electrode, and the degradation rate of ZISTO-2 composite electrode toward MB is maintained at 78.2% after five cycles. The radical trapping experiments indicate that h⁺, ·O²⁻ and ·OH has significant contribution in the photoelectrocatalytic degradation. This paper provides a new ideal way to solve the problem of water pollution under visible light.