Co-doped C3N5 with enhanced RhB degradation by activating PMS

Abstract

The application of advanced oxidation processes in wastewater treatment has attracted wide attention, in the past year. With excellent photoelectric properties and catalytic stability, graphitic carbon nitride and its derivatives have high catalytic performance. Compared to traditional g-C₃N₄ materials, g-C₃N₅ has a narrower band gap (g-C₃N₅ has a band gap of about 2.0 eV and g-C₃N₄ has a band gap of about 2.6 eV) and better electron excitation distribution due to it has a higher proportion of N atoms. In this study, the composites of Co atom doped g-C₃N₅ were synthesized and characterized. Co atoms are successfully doped into g-C₃N₅, which is proved by TEM, XPS and XRD experimental results. PMS can be activated by Co-C₃N₅, and RhB degradation efficiency is as high as 95.8 % within 40 min. The experimental results show that the doping of metal Co can effectively improve the catalytic performance of carbon nitride materials. The degradation efficiency of RHB activated by C₃N₅, C₃N₄ and Co-C₃N₄ was 18.2 %, 11.2 % and 41.8 %, respectively, while the degradation efficiency of Co-C₃N₅ was as high as 95.8 %. RhB was effectively degraded over a wide pH range (3.0–10.9) and under various anion conditions, indicating the excellent environmental suitability of Co-C₃N₅. The results of free radical quenching experiments and EPR tests showed that the contribution of active species to RhB degradation was as follows: SO₄^•− > ¹O₂ > O₂^•−. This paper provides a new perspective using Co-C₃N₅ as a catalyst for PMS-based Fenton reaction.