Green synthesis of ZnO photocatalyst composited carbon quantum dots (CQDs) from lime (Citrus aurantifolia)

Lime (Citrus aurantifolia) is one of the most extensively exported agricultural products from Indonesia. Citric acid and ascorbic acid content from limes (Citrus aurantifolia) is such one of the carbon-rich fruits that is a suitable source for Carbon Quantum Dots (CQDs) synthesis. CQD synthesized by relying on natural carbon precursors from lime (Citrus aurantifolia) is a more environmentally friendly approach in the present research, CQDs in this research will be used as an addition to ZnO by hydrothermal method in order to enhance photocatalytic activity. Corresponding to the results, the presence of CQDs improves both the optical and structural properties of ZnO, which led to enhance photocatalytic activity with a degradation percentage of 98% shortly after 75 min of visible light irradiation and to each of the repeatability test cycle results showing the consistent results and with the rate constant (k) fluctuating and the specified compound's degradation percentage remains relatively constant with minor changes.