Construction of heterostructure CoWO4/g-C3N4 nanocomposite as an efficient visible-light photocatalyst for norfloxacin degradation

[Display omitted] •Visible light active CoWO4 @ g-C3N4 photocatalyst was successfully prepared herein.•CoWO4 nanoparticles distinctly assembled in g-C3N4 nanosheet with good surface interaction.•CoWO4@g-C3N4 shown higher photocatalytic degradation of norfloxacin rather than pristine.•Degradation efficiency was achieved from 97% in the first run to 87% in the fifth run. The CoWO4 nanoparticles assembled with g-C3N4 nanosheets were successfully fabricated by means of a simple hydrothermal method, followed by ultrasonication. The surface topography, crystalline structure, chemical status, and optical properties of as-prepared materials are well characterized herein. These studies unveil the formation of CoWO4 nanoparticles assembled on the surface of g-C3N4 nanosheets with good crystallinity. EDX and XPS studies substantiated that there were no impurities in the synthesized photocatalyst materials. Furthermore, surface topographical (TEM) analysis affirms that CoWO4 nanoparticles were successfully anchored to g-C3N4 nanosheet. This worthy interfacial contact between CoWO4 and g-C3N4 leads the transfer and separation of photo-induced charge carriers. The effect of catalyst loading and initial substrate concentrations on photocatalytic degradation of norfloxacin by as-prepared samples were examined under visible light. We found that the rate of CoWO4 and g-C3N4 photocatalytic degradation of norfloxacin was 3.18 times and 2.69 times higher than that of pure g-C3N4 and CoWO4, respectively. Enhanced photocatalytic activity was because the synergism between CoWO4 nanoparticles and g-C3N4 nanosheets inhibit the fast recombination of photogenerated e−–h+ pairs. In addition, the radical scavenger study substantiates that OH plays dominate role for norfloxacin degradation rather than O2−. A possible mechanism responsible for photodegradation of the Z-scheme was ultimately proposed. This work can be useful in the rational design and delivery of new types of Z-scheme photocatalysts.