Sustainable combustion synthesis of BiVO4 using orange peel for photocatalytic applications
摘要
The transition toward sustainable synthesis routes plays a crucial role in advancing scalable and environmentally responsible photocatalytic materials. In this study, a green combustion synthesis of bismuth vanadate (BiVO4) was developed, using orange peel powder (OPP) as both a renewable fuel and a multifunctional complexing agent. The incorporation of OPP eliminated the need for hazardous reagents and promoted waste valorization, aligning with the principles of green chemistry and the circular economy. Comprehensive structural, morphological, and optical characterizations were performed using XRD, Raman, XPS, FTIR, SEM/TEM, and UV–Vis spectroscopy. An increasing OPP content induced a phase transition from a mixed tetragonal-monoclinic system to a predominantly monoclinic BiVO4 structure, which correlated with improved photocatalytic performance. Although the residual organic components of OPP were not explicitly identified, the data indicated enhanced crystallinity and the formation of oxygen vacancies. These vacancies contributed to bandgap narrowing (2.21 eV), improved charge separation, and reduced electron–hole recombination. The optimized BiVO4 sample (N3-350) exhibited remarkable photocatalytic activity, achieving over 95% degradation of methylene blue and malachite green, and 80% of acid blue 113 under visible-light irradiation. Electrochemical measurements revealed an increase in charge carrier density and favorable band edge alignment, supporting efficient photocatalytic hydrogen evolution (163 μmol H2 g⁻1 h⁻1) and CO2 photoreduction to formic acid (46.9 μmol h⁻1), all without the need for noble metal cocatalysts. This green synthesis approach for BiVO4 demonstrates the effectiveness of biomass-derived materials in photocatalytic and environmental applications and provides a viable pathway for sustainable materials design.