Ultrasonic Electrodeposition of Gold-Platinum Alloy Nanoparticles on Ionic Liquid-Chitosan Composite Film and Their Application in Fabricating Nonenzyme Hydrogen Peroxide Sensors

摘要

Gold-platinum nanoparticles(AuPt NPs)were fabricated on chitosan(Ch)-ionic liquid(i.e.,trihexyltet-radecylphosphonium bis(trifluoromethylsulfonyl)imide,[P(C6)3C_(14)][Tf2N])film by using an ultrasonic electrodeposition method for the first time.Ch acted as an adsorbent for the metal ions,and[P(C6)3C_(14)][Tf2N]played a dual role of matrix and stabilizer in the formation of the nanoparticles.The obtained AuPt NPs were characterized by scanning electron microscopy,X-ray photoelectron spectroscopy,and X-ray diffraction.It was found that they were well-dispersed on the composite surface,and their diameters were 10-20 nm.Furthermore,they exhibited the features of an alloy,and the atomic ratio of Au/Pt in the alloy NPs was close to the concentration ratio of AuCLT/PtCl6~(2-)in the solution.Electrochemical observation showed that the AuPt-Ch-[P(C6)3C_(14)][Tf2N]modified glassy carbon electrode(GCE)had a large electroactive surface area and small electron transfer resistance.When the ratio of AuCl4~-/PtCl6~(2-)was around 3:1,the resulting electrode(i.e.,Au3Pt1-Ch-[P(C6)3C_(14)][Tf2N]/GCE)displayed high catalytic activity to the reduction of hydrogen peroxide(H2O2).Chronoamperometric experiments showed that at an applied potential of 0.05 V(vs SCE),the reduction current of H2O2 was linear to its concentration in the range of 5-355 nM,and the detection limit was found to be 0.3 nM on the basis of the signal-to-noise ratio of 3.The as-prepared nonenzyme hydrogen peroxide sensor exhibited excellent stability,repeatability,and selectivity.