Synergetic Photocatalytic Activity of Metal-Free Boron Nitride Quantum Dots and Graphitic Carbon Nitride: Harnessing Visible Light for Organic Waste Elimination–A Theoretical and Experimental Approach

Water pollution has become a major concern due to the rapid development of industrialization and rise in chemical use, which poses a great risk to humans and environment. Herein, a novel nanocomposite of metal-free boron nitride quantum dots (BNQDs) supported on graphitic carbon nitride (g-C₃N₄) photocatalyst (BNQDs@g-C₃N₄) was successfully synthesized using a facile and green approach. The prepared nanocomposite exhibited exceptional photocatalytic activity in the degradation of aqueous waste pollutants, including organic dyes and pharmaceuticals under visible light irradiation, its worth mentioning, the rate constant of tetracycline removal was 0.064 mol⁻.L.min⁻¹. The experimental results indicated that the significantly boosted photocatalytic activity of the BNQDs@g-C₃N₄ composite proved the energy gap modulation by the construction of heterojunction between the BNQDs and g-C₃N₄ in s-scheme photocatalyst. Theoretical calculations were done to calculate the crystal, electronic structures, and properties of BNQDs@g-C₃N₄. Theoretical results showed that loading of BNQDs on g-C₃N₄ provides an extended band edges that are more applicable in visible light-based photocatalysis process. Additionally, it offers additional bands that facilitate the passage of electrons between the valance and conduction bands. Finally, a possible s-scheme mechanism of the charge separation improvement was proposed by analyzing the experimental results and theoretical calculations.