Study On Preparation And Performances Of Two Noble Metal Nanoelectrocatalysts

Noble metal nanomaterials have received extensive attention in the fields of material science,biotechnology,environment and energy due to their many characteristics（such as size effect,quantum effect and interface effect）.Improving the utilization of noble metal nanomaterials has been the important research project for years.In this thesis,a brief review is made on noble metal nanoelectrocatalysts,nanoporous metal materials and dynamic hydrogen bubble template method,and underpotential deposition.A three-dimensional honeycomb AuPt noble metal modified electrode was prepared via dynamic hydrogen bubbles and sacrificial metal double template methods,and a PtAu noble metal modified electrode was prepared by metal underpotential/bulk codeposition method.The electrocatalysis and/or electroanalysis performances of small organic molecules（formic acid and formaldehyde）were investigated on these modified electrodes.The main contents are as follows.1.A three-dimensional honeycomb-like porous nano-AuPt Cu（3DHPN-AuPt Cu）composite was electrodeposited on a gold-plated glassy carbon electrode(Au_pla/GCE)by the dynamic hydrogen bubble template method,followed by anodic stripping of Cu to yield a3DHPN-AuPt _Cu/Au_pla/GCE.The relevant modified electrodes were characterized by cyclic voltammetry,metallographic microscopy,scanning electron microscopy（SEM）,energy dispersive spectroscopy（EDS）and inductively coupled plasma-atomic emission spectrometry（ICP-AES）.The electrocatalytic oxidation peak current density on3DHPN-AuPt _Cu/Au_pla/GCE in 0.5 M aqueous H₂SO₄containing 0.2 M HCOOH was 12.5 m A cm _Pt^-2,which is superior to the control electrodes and many reported Pt-based electrocatalysis electrodes.2.The electrochemical behaviors of Bi,Au and Pt on GCE,Au and Pt electrodes were studied by electrochemical techniques.A PtAu _Bi-UPD0composite was electrodeposited on a glassy carbon electrode（GCE）by Bi-underpotential/PtAu-bulk codeposition method,followed by acidic stripping of Bi to yield a PtAu _Bi-UPD/GCE.The relevant modified electrodes were characterized by electrochemical methods,quartz crystal microbalance（QCM）,SEM and EDS.The as-prepared PtAu _Bi-UPD/GCE exhibited high electrocatalytic activity for formaldehyde oxidation in 0.5M aqueous H₂SO₄.Under optimal conditions,the PtAu _Bi-UPD/GCE showed a linear amperometric response to formaldehyde concentration from 0.005 m M to 33 m M,with a sensitivity of 1.72 m A m M^-1cm^-2,a limit of detection（LOD,S/N=3）of 2.2 μM,and good selectivity.