Synthesis of CoWO4/g-C3N4 Z-scheme heterojunction for the efficient photodegradation of diazinon with the addition of H2O2.

ABSTRACT

Pesticides are on the list of substances that are routinely monitored by agencies and organizations in various natural environments and habitats. Diazinon (DZN) is the active ingredient in more than 20 agricultural pesticides, it causes the most damage and has been prohibited in many countries around the world. The final product CoWO4/g-C3N4 Z-scheme heterojunction was successfully synthesized in this work, where CoWO4 nanoparticles were deposited on the surface of g-C3N4. CoWO4/g-C3N4 structure allowed for the efficient separation of photo-generated electron-hole pairs, with electrons at the CoWO4 CB migrating to the g-C3N4 VB and preserving the electrons at the g-C3N4 CB and holes in the CoWO4 VB. The photodegradation efficiency of DZN using CoWO4/g-C3N4 Z-scheme heterojunction was investigated, as compared with its precursors, such as CoWO4, and g-C3N4. CoWO4/g-C3N4 Z-scheme heterojunction demonstrated the highest degradation capacity for DZN removal. Based on the results, the photocatalysis of the CoWO4/g-C3N4 Z-scheme heterojunction can be recycled for the effective removal of DZN by simple washing after three runs, proving the heterojunction's stability and suggesting CoWO4 as a promising material for the removal of DZN from contaminated water sources.