Low bandgap microsphere-like magnetic nanocomposite: An enhanced photocatalyst for degradation of organic contaminants and fabrication of SERS-active surfaces

Abstract

The coupling of both photocatalysis and SERS analysis applications may provide a promising technology in the remediation of recalcitrant organics in aqueous systems and simultaneously serve as rapid on-site quantitative analysis. In this work, we present a simple method to synthesize a multi-functional material via modification of the broad bandgap of titanium dioxide (TiO2) through semiconductor coupling using tungsten disulphide (WS2) and magnetic (Fe3O4) nanoparticles. Based on ultraviolet irradiation, the novel microsphere-like magnetic Fe3O4@TiO2/WS2 hybrid nanoparticles, termed as (MNPs) was used as photocatalyst for photocatalytic degradation of organic compounds. Moreover, with the aid of photoreduction; we were able to synthesize and overgrow silver nanoparticles (AgNPs) on the MNPs to obtain surface-enhanced Raman scattering (SERS) platform (Ag@MNPs) for more accurate, rapid, on-site and salable quantitative analysis of rhodamine B (RhB). Our findings demonstrated that the created reduction relevant to TiO2 bandgap energy thus improved its photocatalytic activity and the presence of AgNPs developed a highly sensitive, stable, and reproducible SERS-active substrate. Furthermore, a significantly strengthened photo-degradation of non-steroidal anti-inflammatory drugs, antibiotics and a cosmetic dye have been illustrated. Easy separation, low cost, high efficiency, reproducibility, and sustainability are the main advantages of the Fe3O4@TiO2/WS2 nanophotocatalyst. The removal efficiencies between 68–100% were obtained for drugs and dye in the range of 60 and 200 min under ultraviolet-irradiation. In addition, well dispersed ultra-small Ag NPs decorated MNPs were obtained from this in-situ strategy that showed high levels of SERS activity with the ability to detect RhB with a concentration limit of 10 nM using an excitation wavelength of 532 nm.