One-step green synthesis of silver nanobelts assisted by sodium carboxymethylcellulose for catalytic reduction of 4-nitrophenol

Abstract

Large-scale silver nanobelts (AgNBs) were prepared by a one-step method at near room temperature with high catalytic activity for 4-nitrophenol (4-NP) reduction to 4-aminophenol. This strategy was simple and green owing to the reasonable application of sodium carboxymethylcellulose (CMC) as a structure-directing agent and ascorbic acid (AA) as a reducing agent, avoiding extreme temperatures, tedious procedures, environmentally unfriendly additives, organic solvents and complicated apparatus. Most AgNBs reached lengths of 50 μm with some reaching ∼86 μm; these AgNBs were produced from large round nanoplates with thicknesses of ∼58 nm. By tuning the CMC concentration, AgNO₃/AA ratio and temperature, the product morphology changed from one-dimensional nanobelts to three-dimensional pie-like, brick-like and hierarchical microstructures. Benefiting from their slender and unique laced structure, the AgNBs showed superior catalytic activity for 4-NP reduction. Additionally, the reaction rate constant and activity factor of the AgNBs reached 1.74 × 10⁻² s⁻¹ and 87.00 s⁻¹ g⁻¹, respectively (∼11.75, 6.61 and 8.13 times higher than the activities of the pie-like, brick-like and hierarchical Ag microstructures). This method not only successfully prepared AgNBs using a simple, green approach, further broadening the application of CMC to control metal nanomaterial morphologies, but may also be applied to the preparation of other kinds of nanomaterials.