Chelating agent (EDTA) assisted Bi₂WO₆ nanomaterials (EDTA-BWO) is synthesized using the hydrothermal method. The EDTA-BWO shows fast catalytic reduction of 4-nitrophenol (4-NP), methyl orange (MO), congo red (CR), and [Fe(CN)₆]³⁻ that proceeds through electron transfer mechanism. The catalyst can be reused up to five times without significant loss of activity.

Abstract

We report a chelating agent-assisted synthesis of Bi₂WO₆ nanomaterials using a facile hydrothermal method. The presence of a chelating agent (EDTA) influences the degree of crystallinity, morphology, and surface area of Bi₂WO₆. Analysis by electron microscopy revealed morphological changes of Bi₂WO₆ from flower-like to multilayered disc-like structures after introducing EDTA. The surface area of pristine Bi₂WO₆ NMs is significantly increased from 31 to 50 m² g⁻¹. We demonstrated the catalytic properties of Bi₂WO₆ and EDTA-Bi₂WO₆ for 4-nitrophenol (4-NP), methyl orange (MO), congo red (CR), and [Fe(CN)₆]³⁻ reductions in the presence of NaBH₄. It was observed that EDTA-Bi₂WO₆ exhibited higher catalytic activity compared to the pristine Bi₂WO₆ NMs. The reduction reactions followed pseudo-first-order kinetics and the rate constant values of EDTA-Bi₂WO₆ for 4-NP, MO, CR, and [Fe(CN)₆]³⁻ reductions were found to be 0.847, 0.584, 0.702, and 0.463 min⁻¹, respectively. The reduction proceeds through electron transfer process over an EDTA-Bi₂WO₆ catalyst in the presence of NaBH₄. Furthermore, EDTA-Bi₂WO₆ also showed ultrafast catalytic performance to dichromate (Cr₂O₇ ²⁻) reduction, compared to pristine Bi₂WO₆. The EDTA-Bi₂WO₆ catalyst could be recycled up to five times without undergoing a significant loss in activity.