In situ fabrication of Ag nanoparticles/attapulgite nanocomposites: green synthesis and catalytic application

A facile solvents-free reaction method was employed to in situ prepare Ag nanoparticles/attapulgite (Ag-NPs/APT) nanocomposites and used for the catalytic reducing decoloration of Congo red (CR) dye. The Ag-NPs with different sizes and loading amounts were in situ formed by the thermal decomposition of silver acetate with no need of any chemical solvent, reductant, stabilizer, or electric current; and the formed Ag-NPs were uniformly immobilized on APT as shown by X-ray diffraction and transmission electron microscopy analyses. The nanocomposites show excellent catalytic activity to catalytic reducing CR dye in the presence of NaBH₄, and the CR solution (20 mg/L) can be rapidly decolored within 2 min at the lower dosage of nanocomposite (0.3 g/L). The electron transfer from BH₄ ⁻ to the electron acceptor CR, mediated by Ag-NPs, represents the main reduction mechanism. The nanocomposite still shows better catalytic activity after ten cycles, hence it can be used as a recycle material for catalytic applications.