Epitaxial construction of BiPO4@Bi(OH)3vac S-scheme heterojunction with firm interfacial contact for bolstered photocatalytic performance
Potlako J. Mafa, Mope E. Malefane, Adewale O. Oladipo, Sogolo Lucky Lebelo, Dan Liú, Jianzhou Gui, Bhekie B. Mamba, Alex T. Kuvarega
Abstract
One of the prerequisites for high charge separation and stability in photocatalysis is achieved through the construction of heterojunction photocatalysts with firm interfacial contact. In this study, the epitaxial growth method was utilized to prepare BiPO 4 @Bi(OH) 3vac (BPBOH vac ) S-scheme heterojunction with firm interfacial contact and effective interfacial charge transfer (IEF). The success of epitaxial growth was observed through new bond formation in Fourier transform infrared spectroscopy (FTIR). The prepared catalyst degraded chlortetracycline (CTC) with an efficiency of 94.25 % (0.0271 min 1 ). The high performance was attributed to high charge transfer dynamics as indicated by Linear sweep voltammetry (LSV), Tafel polarization curves, and electrochemical impedance spectroscopy (EIS); remarkable stability, and presence of oxygen vacancies . The S-scheme heterojunction photocatalyst achieved more than 90 % when it was tested against other organic pollutants , unequivocally revealing its capabilities. The S-scheme heterojunction system exhibited reasonable efficacy in different water sources and the presence of inorganic ions , rendering the system applicable to environmental conditions. Based on the information from XPS , Mott-Schottky (M-S), and trapping experiments, a tentative degradation mechanism of CTC by the BPBOH vac -3 was proposed. LC-MS studies provided information on the degradation pathways and identity of the by-products. Toxicity studies confirmed the non-toxicity of the prepared photocatalysts. Thus, this study highlights the potential engineering of novel inorganic heterojunctions through the epitaxial growth for the removal of pharmaceuticals and sheds some light on the new avenues for the preparation of similar materials for environmental applications.