Constructing defective-functionalized g-C3N4 homojunction for efficient photocatalytic detoxification of lemon yellow in an aqueous solution and beverage

The content of food colorant in food and environment should be limited to a safe range. Thus, cost-effective, and environmental-friendly detoxification technology is urgent for food safety and environmental protection. In this work, defective-functionalized g-C3N4 was successfully fabricated via intermediate engineering strategy. The prepared g-C3N4 possesses large specific surface area with abundant in-plane pores. Carbon vacancy and N-CO unit are introduced into g-C3N4 molecular framework, endowing the different degrees of n-type conductivity in varied domains. And then the n-n homojunction is generated. This homojunction structure is demonstrated to be efficient in separation and transfer of photoinduced charge carriers, and causes enhanced photocatalytic detoxification of lemon yellow under visible light. Furthermore, as-prepared g-C3N4 in lemon tea enable completely removed lemon yellow without obvious effect on its overall acceptability. The findings deepen the understanding on the defect-induced self-functionality of g-C3N4, and prove the application potential of photocatalytic technology in contaminated beverages.