Tween-85 Surfactant-Assisted Fabrication of Silver Monoliths for Catalytic Reduction of Methyl Orange and Caffeine Sensing

摘要

An elegant method (modified sol-gel method) was developed to fabricate porous silver (Ag) monoliths using Tween-85 (T-85) as a reducing agent with and without dextran (Dex) and TiO2nanoparticles (TiO2NPs) for heterogeneous catalysis for the reduction of methyl orange (MO) using sodium borohydride (NaBH4), as reducing agent and also sensor against caffeine. Ag/Tween-85/Dextran/TiO2NPs (Ag/T-85/Dex/TiO2NPs) catalyst was characterized by thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) adsorption isotherm technique, and Fourier transform infrared (FTIR) analysis. Porous Ag/T-85/Dex/TiO2NPs monolith degraded toxic dye methyl orange just in 25 seconds (s) which is the minimum time reported. Cyclic voltammetry (CV) using modified carbon paste electrode (CPE) together with Ag/AgCl as reference and pt as counter electrodes with 0.1 m H2SO4 as supporting electrolyte were used. Ag/T-85/Dex/TiO2NPs-CPE acts as a sensor against caffeine with a limit of detection (LOD) and limit of quantization (LOQ) 0.654 ngmL~(-1) and 0.876 ngmL~(-1) respectively and sensitivity is 0.236 μA/mm/cm~2.