Issues of Using Benzyl Ether in Nanomaterials’ Synthesis: Insights for a Standardized Synthesis of FeWOx Nanocrystals and Their Use as Photocatalysts
Raúl Boix, M. Pilar Lobera, María Bernechea. ACS Omega, 2025, 10, 47609–47622.
The synthesis of nonstoichiometric FeWOx nanocrystals via thermal decomposition in benzyl ether has been systematically optimized, addressing reproducibility issues typically associated with this solvent. A key finding of this work is the identification of benzoic acid, a benzyl ether oxidation byproduct, as a necessary ligand for stabilizing tungsten intermediates and enabling consistent FeWOx formation. The optimized protocol allows fine-tuning of the Fe/W atomic ratio, leading to a series of materials with tailored stoichiometry, surface properties, and electronic structure. Fe1.5WOx, Fe1.0WOx, and Fe0.1WOx have been selected as representative examples of materials with Fe excess, slight Fe excess, and an Fe/W ratio close to 1. Among them, Fe0.1WOx exhibited the best photocatalytic performance in the degradation of rifampicin under simulated solar irradiation, achieving a 67% degradation within 150 min and displaying a kinetic rate constant (0.0076 min–1) three times higher than the other compositions. This superior activity is attributed to its reduced band gap (1.45 eV) and favorable band-edge positions. Scavenger experiments confirmed that holes and hydroxyl radicals (•OH) are the main reactive species involved in the degradation process. These findings provide key insights for designing reproducible benzyl ether-based syntheses and demonstrate the potential of FeWOx nanomaterials for photocatalytic water treatment applications.
The synthesis of nonstoichiometric FeWOx nanocrystals via thermal decomposition in benzyl ether has been systematically optimized, addressing reproducibility issues typically associated with this solvent. A key finding of this work is the identification of benzoic acid, a benzyl ether oxidation byproduct, as a necessary ligand for stabilizing tungsten intermediates and enabling consistent FeWOx formation. The optimized protocol allows fine-tuning of the Fe/W atomic ratio, leading to a series of materials with tailored stoichiometry, surface properties, and electronic structure. Fe1.5WOx, Fe1.0WOx, and Fe0.1WOx have been selected as representative examples of materials with Fe excess, slight Fe excess, and an Fe/W ratio close to 1. Among them, Fe0.1WOx exhibited the best photocatalytic performance in the degradation of rifampicin under simulated solar irradiation, achieving a 67% degradation within 150 min and displaying a kinetic rate constant (0.0076 min–1) three times higher than the other compositions. This superior activity is attributed to its reduced band gap (1.45 eV) and favorable band-edge positions. Scavenger experiments confirmed that holes and hydroxyl radicals (•OH) are the main reactive species involved in the degradation process. These findings provide key insights for designing reproducible benzyl ether-based syntheses and demonstrate the potential of FeWOx nanomaterials for photocatalytic water treatment applications.