Synthesis of quantum dot-based CuO/Fe₃O₄@g-C₃N₄ dual Z-scheme ternary composite from Aloe vera

CuO/Fe₃O₄@g-C₃N₄ ternary composite was synthesised via an ex-situ hydrothermal method by using Aloe vera leaf extract as a reducing and stabilising agent. Morphological investigations of CuO/Fe₃O₄@g-C₃N₄ showed spherical-shaped quantum dot-sized (3.34 ± 0.98 nm) metallic oxides uniformly dispersed on g-C₃N₄. Incorporating CuO and Fe₃O₄ quantum dots onto g-C₃N₄ resulted in a dual Z-scheme heterostructure with decreased bandgap energy (2.66–1.67 eV). This work is significant as it demonstrated a simple, one-step ex-situ green synthesis of a dual Z-scheme CuO/Fe₃O₄@g-C₃N₄ heterostructure. It is known in literature that g-C₃N₄ suffers from quick recombination of photoexcited charges and over the years these have been improved using modification strategies such morphologies regulating, element doping and heterojunctions construction. Dual Z-scheme heterojunctions have advantageous properties such as reduced bandgap energy, increased separation rate of photogenerated electron-hole pairs and efficient redox reactions, compared to other heterojunctions that suffer from limitations such as low charge separation efficiency. It is envisaged that this dual Z-scheme ternary composite will be incorporated into a hollow fiber membrane for application in the degradation of antiviral drugs, which will be addressed separately and is not included in the present manuscript.