The Fabrication Of Nanoporous Gold Based Electrodes For Nonenzymatic Glucose Detection

Nanoporous gold(NPG)not only has conductivity and malleability as bulk gold,but also has some unique nature as nanomaterials,such as small size effect,surface effect,quantum size effect and quantum tunnel effect.The current methods to fabricate NPG electrodes can be categoried to dealloying method,templating method and electrochemical method.The last method is relatively simple and environmentally friendly,because it avoids the disadvantages of multi-step template treatment or multi-component alloy preparation.This paper aims to build NPG or NPG based electrode and study their catalytic performances towards glucose,and further explore its potential application in electroanalysis.The main contents are summarized as follows:(1)Preparation of a Ni(OH)2 modified NPG(Ni(OH)2/NPG)composite electrode by one-step anodic potential method in NiCl2 solution.During the process of preparation,the nanoporous structure was formated on surface of gold,at the same time the Ni2+reacted with the OH-which was from cathode to form Ni(OH)2 and was anodically adsorbed on the NPG surface The surface morphologies and chemical component of Ni(OH)2/NPG were characterized by SEM,TEM and XPS.Electrooxidation behaviors of glucose on NPG and Ni(OH)2/NPG in NaOH solution were compared,and nonenzymatic detection of glucose has been conducted under alkaline conditions.(2)Preparation of a Ni modified NPG(Ni/NPG)composite electrode by double-potential step method in a mixture solution containing KCl and NiCl2.The step time and the the concentration of electrolyte that can impact on the active area of NPG were studied in detail.Electrooxidation behavior of glucose in NaOH were detailed compared between NPG and Ni(OH)2/NPG electrodes,and nonenzymatic detection of glucose has been conducted under alkaline conditions.(3)A gold nanoparticles modified NPG(nanoAu/NPG)electrode with a high specific surface area was prepared with one-step by treating a smooth Au80Sn20 electrode with an anodic pontial in 2 M HCl solution.During the anodic process,Sn2+was anodically dissolved and reacted with AuCl4-to form Au nanoparticles,which were spontaneously adsorbed on nanoporous substrate.The step time and the the concentration of HCl electrolyte that can impact on the active area of nanoAu/NPG were studied.Electrooxidation behaviors of NPG and nanoAu/NPG towards glucose in NaOH were detailed compared by CV,and nonenzymatic detection of glucose has been conducted under alkaline conditions.(4)A NPG electrode with a high surface area was prepared with one step by square wave potential pluse in 0.2 M phosphate buffer solution(PBS,pH 7.5).The pluse potential,pluse time and the the concentration of PBS that can impact on NPG roughness were studied in detail.SEM was used to characterize the morphology of as-prepared NPG.CV was applied to illustrate the electrochemical behavior of glucose on NPG electrode,and nonenzymatic detection of glucose has been conducted under alkaline conditions.