纳米银粒子的绿色制备及其对4-硝基苯酚的催化还原性能研究OA北大核心CSTPCD

Silver nanoparticles(AgNPs)were synthesized using carboxymethyl chitosan(CMC)as re-ducing agent and stabilizer.The effect of reaction temperature,time and molecular parameters(substi-tution degree and molecular weight)of CMC were investigated.AgNPs were characterized by UV-vis spectroscopy(UV-vis),Transmission electron microscopy(TEM),Fourier transform infrared spec-troscopy(FT-IR)and X-ray diffraction(XRD).The catalytic reduction of 4-nitrophenol(4-NP)in aqueous by AgNPs prepared under different conditions was investigated.The results showed that spher-ical or close-to-spherical AgNPs with an average particle size of about 10 nm can be prepared by using different molecular parameters CMC as reducing agent and stabilizer.The size and productivity of Ag-NPs can be controlled by adjusting the reaction temperature,time and the molecular parameters of CMC.The size of AgNPs increased with the increase of CMC.The average particle size of AgNPs was the smallest,(5.1±1.2)nm,when CMC with molecular weight of 612.2 kDa was used as reducing agent and stabilizer.The catalytic activity of AgNPs for 4-NP in aqueous increased with the decrease of particle size.When AgNPs with average particle size of(5.1±1.2)nm were used as catalyst,the con-version of 4-NP was 98.8%after 20 minutes of catalytic reaction and the reaction rate constant was 0.231 6 min-1.