Facile synthesis of strontium molybdate coupled g-C3N4 composite for effective tetracycline and dyes degradation under visible light

Abstract

This work was designed to synthesize SrMoO4/g-C3N4 heterojunction for efficient degradation of tetracycline (TC) hydrochloride via photocatalysis. SrMoO4/g-C3N4 samples were prepared through a grinding and roasting process. The prepared nanocomposite exhibited excellent visible-light-driven photocatalytic activity. The reaction rate of TC photodegradation reaches 0.0171 min−1, which is 5.9 times higher than that of neat g-C3N4. The origin of the high photoactivity of SrMoO4/g-C3N4 was investigated using a variety of characterization techniques including XRD, FT-IR, TG, SEM, TEM, XPS, DRS, Mott-Schottky, PL, PC, and EIS. Result showed that the added SrMoO4 was closely loaded on the g-C3N4 surface, which is conducive to the electron transfer between SrMoO4 and g-C3N4. Mott-Schottky analysis indicated that SrMoO4 has a lower conduction band (CB) position than g-C3N4. As a result, photogenerated electrons in g-C3N4 can move to the CB of SrMoO4 to hinder the recombination of charge carriers, thereby increasing the photocatalytic activity under visible light. The cycling test further suggested that the SrMoO4/g-C3N4 heterojunction has good stability in the photocatalytic degradation of TC. Super oxygen radicals and holes are the main reactive species.