Enhancement of photocatalysis performance of CdIn₂S₄/g-C₃N₄ heterojunction by H₂O₂ synergism

A highly efficient binary CdIn₂S₄/g-C₃N₄ heterojunction photocatalyst was synthesized by a simple wet impregnation method. Photocatalytic system based on the synergistic action of binary CdIn₂S₄/g-C₃N₄ heterojunction and H₂O₂ was proposed to improve the degradation effect of dyes. The photocatalytic activity was evaluated by the degradation of methyl orange(MO) under visible light irradiation. The results demonstrated that contrasted to pure g-C₃N₄, the synthesized heterojunction can significantly improve the photocatalytic activity. After 120 min of irradiation by visible light, the photocatalytic efficiency of MO degradation of 7CIS/CN was 3.13 times higher than that of g-C₃N₄. When 60 mM H₂O₂ was added on this basis, the photocatalytic efficiency increased from 93.81 to 99.40%. The improvement of photocatalytic activity is attributed to the formation of binary CdIn₂S₄/g-C₃N₄ heterojunction to promote the transfer of photogenerated electron-hole pairs, and an appropriate amount of H₂O₂ as an electron trap further reduced the recombination rate of photogenerated electron-hole pairs. Active species capture experiments showed that ·O₂⁻ are the main active substances. Subsequently, the mechanism of photocatalytic degradation was proposed. This work provided a new efficient strategy for the degradation of industrial dye wastewater.