Potassium Poly(heptazine imide) Coupled with Ti3C2 MXene-Derived TiO2 as a Composite Photocatalyst for Efficient Pollutant Degradation.

Abstract

The photocatalytic degradation of pollutants is an effective and sustainable way to solve environmental problems, and the key is to develop an efficient, low-cost, and stable photocatalyst. Polymeric potassium poly(heptazine imide) (K-PHI), as a new member of the carbon nitride family, is a promising candidate but is characterized by a high charge recombination rate. To solve this problem, K-PHI was in-situ composited with MXene Ti3C2-derived TiO2 to construct a type-II heterojunction. The morphology and structure of composite K-PHI/TiO2 photocatalysts were characterized via different technologies, including TEM, XRD, FT-IR, XPS, and UV-vis reflectance spectra. Robust heterostructures and tight interactions between the two components of the composite were verified. Furthermore, the K-PHI/TiO2 photocatalyst showed excellent activity for Rhodamine 6G removal under visible light illumination. When the weight percent of K-PHI in the original mixture of K-PHI and Ti3C2 was set to 10%, the prepared K-PHI/TiO2 composite photocatalyst shows the highest photocatalytic degradation efficiency as high as 96.3%. The electron paramagnetic resonance characterization indicated that the·OH radical is the active species accounting for the degradation of Rhodamine 6G.