Application of Z–Scheme CdSWO₃ Nanocomposite for Photodegradation of Ethylparaben under Irradiation with Visible Light: A Combined Experimental and Theoretical Study

Abstract

The CdS- WO3 nanocomposite was successfully synthesized using the hydrothermal method. The catalytic capacity of CdS- WO3 nanocomposite was evaluated based on various parameters, such as pH, catalyst load, bicarbonate and persulfate concentrations. The ratios of CdS to WO3 was also examined to acquire the photocatalytic performance in addition, the by–products and pathway were also studied. The findings showed that CdS- WO3 (ratio 3:7) produced better photodegradation performance in comparison to CdS- WO3 (ratio 1:1). Also, from the same investigation, the CdS- WO3 nanocomposite exhibited a slightly higher catalytic ability in the presence of 150 mg L–1 S2O82– ions (at pH 3) than with bicarbonate ions. A 40% degradation was observed in the presence of 150 mg L–1 S2O82– ions (at pH 3). Moreover, about 38% of adsorption was observed with bicarbonate ions. In this study, we systematically reveal the underlying mechanism of the improved photoactivity of CdS–WO3 nanocomposite using a hybrid density functional theory calculation. The interfacial interaction led to the formation of a built–in internal electric field at the CdS–WO3 interface to promote the separation of charge carriers, The theoretical results rationalise the experimental findings and offer a new understanding of the underlying mechanism of the photoactivity of CdS–WO3 nanocomposite. The degradation pathway of Ethylparaben, which involved dealkylation of ethyl unit was proposed.

Novel Z-scheme Co3O4/WO3 nanocomposite performance in adsorption and photocatalytic degradation of ethylparaben and methylene blue in water

“…Recently, the coupling of semiconductor with different band gaps revealed that it can suppress the charge carrier recombination rate. Several researchers have reported the application of WO 3 nanocomposite with other semiconductors in the photodegradation of organic pollutants [30][31][32][33], gas sensing [34], pharmaceutical [35,36], and photoelectrochemical applications [37,38]. Tricobalt tetroxide (Co 3 O 4 ) is a p-type semiconductor that possesses unique characteristics of high stability (thermal and chemical), low solubility, catalytic properties [39] as well as having a narrow band gap (2.1 eV) and various oxidation states [40].…”