Novel CoWO4-Ag2MoO4 NCs: Synthesis, enhanced photocatalytic activity under visible-light irradiation and its antimicrobial activity

Abstract

A novel CoWO4-Ag2MoO4 nano-heterostructure was synthesized by chemical co-precipitation method for improved photocatalysis and antibacterial applications. High-resolution transmission electron microscopic (HRTEM) analysis revealed the intimate contact of pristine NPs that could facilitate transfer of e−/h+ pairs at interface which in turn improve lifetime of charge carriers. X-ray powder diffraction (XRD) reveals the co-existence of CoWO4 and Ag2MoO4 with crystalline nature. UV–vis diffuse reflectance spectroscopy (DRS) indicates that the band gap of nano-heterostructure was shifted to visible-light range for effective utilization of solar energy. Energy-dispersive X-ray spectroscopy (EDAX) and X-ray photoelectron spectroscopy (XPS) verified the elements and its chemical states. BET analysis indicates the increased active sites in CoWO4-Ag2MoO4 surface. The photodegradation of MB by CoWO4-Ag2MoO4 nanocomposite (NCs) (90.5%) was fond to be efficient than CoWO4 (70%) and Ag2MoO4 (26.5%). CoWO4-Ag2MoO4 exhibited excellent stability and recyclability with resistant to photo-corrosion and it was confirmed by six recycles test. The NCs exhibited excellent antimicrobial activity against Escherichia coli and Bacillus subtilis. The systematic study on the radical scavenging assay showed that the formation of hydroxide radical played the crucial role on the photocatalytic degradation of methylene blue dye by CoWO4-Ag2MoO4 NCs. The higher reduction potential of CoWO4 (EVB=2.86 eV) enhance the formation of hydroxy radical, which interact with MB dye for the effective degradation. The enhanced visible-light harvesting and operation simplicity prompted CoWO4-Ag2MoO4 NCs as a promising candidate for photodegradation of toxic organic contaminants and for antimicrobial applications.