Abstract
The growing energy crisis necessitates renewable and eco-friendly alternative such as green hydrogen. Herein, a Zn3(PO4)2-red dragon fruit peel extract (ZP-DF) nanocomposite was evaluated for green hydrogen production from coconut water waste via electro-photocatalysis. UV-Vis spectroscopy revealed good nanocomposite stability, with particle diameters of 18.79-75.14 nm and band gap energies of 2.52-2.94 eV. FTIR spectra confirmed antisymmetric PO43−stretching at 1018-1024 cm-1, distinct from the DF extract spectrum, alongside a characteristic band at 633-635 cm-1attributed to Zn. XRD analysis identified the hopeite crystal phase of Zn3(PO4)2, with crystallitesize of 41.28 -95.13 nmwhile digital optical microscopyrevealed a non-uniform grain morphology. Electrophotocatalysis using aZP-DF10-coated electrode produced 36.7 ppm H2from pure water waste (1.8 mL/min,46.21%efficiency)and 30.4 ppm H2from coconut water waste (0.6 mL/min, 31.03%efficiency). In contrast,conventional electrolysis without the photocatalyst yielded only 24.4 ppm(0.2 mL/min)and 23.2 ppm (0.3 mL/min) H2from pure water and coconut water waste, respectively.These results demonstrate that ZP-DF nanocomposite significantly enhances green hydrogen production via electrophotocatalysis, offering a promising, sustainable route for waste-derived renewable energy generation.