A novel Ti3C2 MXene/PDI supramolecules composite with enhanced photocatalytic activities for degradation of tetracycline hydrochloride under visible-light

Abstract

Ti3C2 MXene/Perylene diimide supramolecules (Ti3C2/PDIsm) heterojunction photocatalyst was synthesized by in-situ self-assembly strategy. Under visible light, all Ti3C2/PDIsm with different ratio exhibited higher photocatalytic activity and stability than pure PDIsm. Among them, composite with Ti3C2 proportion of 15 wt% had the highest degradation rate of tetracycline hydrochloride (TC-H), which was 65.3 % higher than pure PDIsm. The characterization results showed that the improved photocatalytic performance was due to the formation of Schottky junction between PDIsm and Ti3C2, which caused the excited electrons in PDIsm to transfer to Ti3C2, thereby improving the electron-hole pair separation and enhancing the electron mobility. In addition, Ti3C2 also enhanced the light absorption of PDIsm and reduced the band gap energy from 1.64 eV to 1.56 eV. Trapping experiments revealed that ·O2- played a major role in the degradation process of TC-H. All in all, Ti3C2 improved the degradation rate of TC-H by acting as a co-catalyst in the Ti3C2/PDIsm photocatalytic system, and this work provided a reference for the development of novel Schottky junction photocatalysts.