Photocatalytic degradation of malachite green using FeWO4 composite under UV irradiation: experimental study and analysis using density functional theory
摘要
The structural, electriconic, and photocatalytic properties of coprecipitated FeWO4 for malachite green (MG) degradation in water were investigated experimentally and by firstprinciples calculations. The material was synthesized by coprecipitation and characterized by XRD, FTIR, SEM–EDS, and BET surface area analysis. Photocatalytic tests under UV irradiation (254 nm) examined the effects of material loading and solution pH, achieving a maximum MG removal of 98% at pH 3 after 180 min using 1 g L−1 of FeWO4. COD measurements confirmed substantial mineralization, while scavenger experiments identified photogenerated holes (h+) as the dominant reactive species. Density functional theory calculations reproduce the experimental crystal structure and reveal a spinpolarized semiconducting character with band gaps of 2.528 eV (spinup) and 1.4319 eV (spindown). By comparison, the experimentally measured optical gap is 2.88 eV, closer to the spinup channel, supporting strong exchangedriven spin asymmetry. Overall, these results highlight FeWO4 as a promising material with potential for spindependent electronic and photocatalytic applications.