1. Eco-Friendly Coffee Waste-Based Carbon Dots Coupled to ZnBi-Layered Double Hydroxide Heterojunction: Enhanced Control of Interfacial Charge Transfer for Highly Efficient Visible-Light Catalytic Activity
- Author
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Nguyen Thi Thanh Huong, Dang Nguyen Nha Khanh, Ngo Thi Tuong Vy, Le Hai Khoa, Nguyen The Anh, Dang Vu Bao Tran, Tong Pham Phuong Thuan, Le Khue Tu, Nguyen Thanh Ha, Nguyen Ngoc Nghia, and Nguyen Thi Kim Phuong
- Subjects
Chemistry ,QD1-999 - Abstract
Using a simple, low cost, and excellent efficient approach, carbon dots (CDs) were fabricated via a one-pot hydrothermal process of coffee waste. Amazingly, the combination of 2% CDs with ZnBi2O4 to form a new and excellent heterogeneous photocatalyst enabled the complete decomposition of 2, 4-dichlorophenoxyacetic acid (2, 4-D) into CO2 and H2O. The findings of this study provide a new perspective on the utilization of agricultural waste for creating products of scientific and practical significance. More than 91% of 2, 4-D (initial concentration of 30 mg/L) was completely decomposed and dechlorinated using 1.0 g/L of CDs (2%)-ZnBi2O4 at pH 4.0 after 120 min of exposure to visible light (with k = 0.0178 min−1), and more than 86% of the decomposed 2, 4-D was mineralized into CO2 and H2O. There was no sign of catalyst deactivation after four cycles of reuse, demonstrating the durability and efficiency of CDs (2%)-ZnBi2O4. The significant improvement in the photocatalytic efficiency of CDs (2%)-ZnBi2O4 compared with that of bare CDs or ZnBi2O4 is due to the formation of defects at the interfaces of the heterojunction; therefore, the movement of photogenerated electrons at the interface between the two components is rapid. The mineralization of 2, 4-D by CDs (2%)-ZnBi2O4 upon exposure to visible light is induced mainly by the photogenerated holes, followed by O2•−, and finally OH• radicals.
- Published
- 2024
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