Unveiling the origin of high-efficiency charge transport effect of C3N5/C3N4 homojunction for activating peroxymonosulfate to degrade atrazine under visible light

Photocatalytic activation of PMS is a potential advanced oxidation process in refractory wastewater purification. Herein, a C3N5/C3N4 homojunction (AT-CN) catalyst as an efficient photocatalyst for PMS activation is reported, which owns interlaced band structure, high-efficiency charge transfer, and PMS activation capability. This homojunction structure is demonstrated to be highly efficient in charge transfer and separation. As experimental result, the reaction rate constants of atrazine in AT-CN/PMS/Vis system increased to 2.9-fold and 7.4-fold, compared with C3N4/PMS/Vis and C3N5/PMS/Vis system. The photocatalytic activation of PMS for atrazine removal efficiency reached 97 % within 60 min (under pH = 3). The band structure, the charge density dif-ference, the PMS adsorption behavior of AT-CN, and the activation pathways of PMS have been studied through the DFT calculation. According to experimental and DFT simulation, the AT-CN homojunction not only suppress the charge recombination via built-in electric field, but also exhibited a better PMS activation capability. In brief, this study through the combination of experiment and simulation is providing more inspiration for designing appropriate nonmetal homojunction in the photo-activated PMS process.

Automated summary

This study reports a C3N5/C3N4 homojunction (AT-CN) catalyst as an efficient photocatalyst for PMS activation. The AT-CN catalyst possesses an interlaced band structure, high-efficiency charge transfer, and PMS activation capability. Experimental results show that the reaction rate constants of atrazine in the AT-CN/PMS/Vis system increased significantly compared to other systems, resulting in a high atrazine removal efficiency of 97% within 60 minutes (under pH = 3). DFT calculations were performed to analyze the band structure, charge density difference, PMS adsorption behavior, and activation pathways of AT-CN, providing insights for designing nonmetal homojunctions in the photo-activated PMS process.