Preparation of C3N4-based photocatalyst for environmental application

Abstract

With the increased global emphasis in tackling water-related issues such as pollution and contamination, it is imperative to discover sustainable solutions in order to protect the scare water sources. A possible solution would be the use of semiconductor-mediated photocatalysis. Semiconductors such as C3N4 and CuS have been studied for their applications in dye and bacteria degradation. However, their applications possess limitations such as high recombination rates of electron-hole pairs and poor absorption efficiency. Hence, it is critical to overcome the limitations to ensure effective applications. This corresponds to the project objective of enhancing the photocatalytic property of C3N4 by the formation of CuS-C3N4 nanocomposite. Characterization tests namely, TEM, SEM, FTIR, XRD, EDX and UV-Vis-DRS were conducted. The results provided strong evidence to suggest the successful adhesion of CuS nanoparticles onto C3N4 sheets and improved absorption intensity of the CuS-C3N4 hybrid materials. To test the performance of the composite material, the project involves the degradation of RhB dye and bacteria by the CuS-C3N4 composite synthesized under solar irradiation. Three samples of different CuS concentrations namely g-C3N4, g-C3N4–CuS-1 and g-C3N4–CuS-2 were used in order to establish the relationship between concentration and level of photocatalytic activity. From the RhB degradation results, it was observed that g-C3N4–CuS-1 has the highest dye degradation efficiency of 86% under solar irradiation. From the bacteria degradation results, minimal bacteria degradation was observed in the absence of solar irradiation and it was observed that g-C3N4–CuS-2 has superior bacteria degradation efficiency than g-C3N4–CuS-1. However, pure g-C3N4 performed better than g-C3N4–CuS composite materials in degrading bacteria. This could be attributed to the high biocompatibility of CuS nanoparticle which resulted in the low toxicity towards bacteria cells.