S-scheme g-C3N4/ZnO heterojunction photocatalyst with enhanced photodegradation of azo dye

Background: The low specific surface area (SSA) and high charge recombination rate of g-C3N4 (hereafter referred to as CN) limit its applications for dye photodegradation. A photocatalyst that enhanced the SSA and retarded the charge recombination rate of g-C3N4 was developed in this study. Methods: In this study, a g-C3N4/ZnO S-scheme heterojunction photocatalyst was prepared via template method. Zeolitic-imidazolate-framework-8 (ZIF8) was used as a template of g-C3N4 and as a precursor of ZnO. This method addressed the two above-mentioned limitations of CN simultaneously. Significant findings: It was confirmed that when calcination temperature was controlled at 450 degrees C, g-C3N4/ ZnO S-scheme heterojunction was successfully fabricated to enhance the specific surface area and charge separation rate of g-C3N4. CN/ZIF8-450 displayed optimal AR1 decolorization performance (95%), which was 1.6 times higher than that of CN (43%), when the reaction time was 1 h. The excellent performance of CN/ ZIF8-450 was attributed to its high specific surface area (182.8 m2/g), 3.4 times higher than that of CN (53.6 m2/g), and low charge recombination rate due to the S-scheme heterojunction. The main reaction species in this system were center dot O2- and h+. This study provided a simple approach to overcoming the limitations of CN in dye wastewater treatment. (c) 2022 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

This study successfully addressed the limitations of g-C3N4, including its low specific surface area and high charge recombination rate, by developing a g-C3N4/ZnO S-scheme heterojunction photocatalyst. The optimized catalyst exhibited excellent decolorization performance for dye degradation.