Photocatalytic performance and degradation pathway of rhodamine B with TS-1/C3 N4 composite under visible light

Abstract

TS-1/C3 N4 composites were prepared by calcining the precursors with cooling crystallization method and were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), UV-Vis diffuse reflection spectrum (DRS) and nitrogen adsorption–desorption isotherm. The photocatalytic performance of TS-1/C3 N4 composites was investigated to degrade Rhodamine B (RhB) under visible light irradiation. The results showed that all composites exhibited better photocatalytic performance than pristine TS-1 and C3 N4; TS-1/C3 N4-B composite (the measured mass ratio of TS-1 to C3 N4 is 1:4) had best performance, with a rate constant of 0.04166 min−1, which is about two and ten times higher than those of C3 N4 and TS-1, respectively. We attributed the enhanced photocatalytic performance of TC-B to the optimized heterostructure formed by TS-1 and C3 N4 with proper proportion. From the results of photoluminescence spectra (PL) and the enhanced photocurrent, it is concluded that photogenerated electrons and holes were separated more effectively in TS-1/C3 N4 composites. The contribution of the three main active species for photocatalytic degradation followed a decreasing order of ·O2−, ·OH and h+. The degradation products of RhB were identified by liquid chromatography tandem mass spectrometry (LC-MS/MS), and the possible photocatalytic degradation pathways were proposed.