Study On Electrochemical Sensing Based On Gold-based Bimetallic Nanomaterials

Gold-based bimetallic nanomaterials modified the glassy carbon electrode（GCE）significantly improve electrochemical sensing performance because the bimetallic nanomaterials possess controllable morphology,good stability,excellent catalysis and electron transport capability.In this paper,gold nanorods（Au NRs）were synthesized by seed-mediated method,and then dendritic gold-palladium（AuPd）,dumbbell-shaped AuPd and dendritic gold-platinum（AuPt）were prepared by simple reduction method.Three new electrochemical sensors were successfully constructed to detect hydroquinone（HQ）,nitrite and tert-butyl hydroquinone（TBHQ）.This study provided a new idea for the synthesis of metal nanocomposites and a reference for the development of high-performance electrochemical sensing.The main work is as follows:1.Highly dispersed gold nanorods（Au NRs）were prepared by seed-mediated method.The dendritic AuPd nanocomposites were successfully synthesized by depositing palladium nanoparticles（Pd NPs）on the surface of gold nanorods and were characterized by the transmission electron microscopy（TEM）and ultraviolet-visible spectrophotometer（UV-vis）.When the molar ratio of Au to Pd was 3:6,the assembled sensor Au₃@Pd₆/GCE had a sensitive response toward HQ in the concentration range of 4-5000μM.2.In order to combine the excellent catalytic performance of Au and Pd,the Pd nanoparticles were obtained by a simple and rapid reduction method,which wrapped around the both ends of Au NRs to form dumbbell-shaped AuPd.The AuPd could rapidly catalyze nitrite ions to be transferred into intonitrate ions.Especially when the molar ratio of Au to Pd is 3:4,the constructed sensor Au₃@Pd₄/GCE exhibited sensitive and stable performance for the detection of nitrite.The corresponding linear range is 2μM-4200μM and the detection limit is 0.67μM.3.The high-dispersion dendritic AuPt was synthesized by an effective reduction method.The platinum nanoparticles were anchored on the surface of the gold nanorods,which effectively increased the specific surface area of the nanomaterials and provided more active sites.Compared with the conventional electrodes,the AuPt modified electrodes possessed significantly better performance.In particular,when the molar ratio of Au and Pt was 3:3,Au₃Pt₃/GCE showed the maximum current response toward TBHQ.The corresponding linear range is from 0.35μM to 625μM and the detection limit is 0.075μM.