【作者】 班彦萍；

【导师】 李怀祥；

【作者基本信息】 山东师范大学 ， 物理化学， 2012， 硕士

【摘要】 光电化学传感器是基于物质的光电转换特性确定待测物浓度的一类检测装置。在分析检测和识别生物分子方面展现了独特的优越性和广阔的应用前景。过氧化氢（H₂O₂）在食品工业、临床应用、环境分析等领域有着广泛的应用。发展可靠、灵敏、快速、低成本的H₂O₂检测方法具有重要的实际意义。普鲁士蓝及其类似物（MHCF），具有较高的电化学可逆性，用作电子传递的媒介，可降低氧化还原物质特别是过氧化物电化学反应的过电位，在较低的电位下能加速电子的传递，对H₂O₂的电催化氧化-还原具有高度的选择性和高效性而被誉为“人工过氧化物酶”。本文主要探讨了两种硅基（n-n⁺-Si和n-Si）的光电极。通过真空蒸镀的方法分别在n-n⁺-Si、n-Si表面修饰Pt、Ni、Pt-Ni合金的金属膜后作为基体电极，在镀金属薄膜的表面再修饰普鲁士蓝或铁氰化镍薄膜形成复合光电极。实验采用两电极体系，以复合光电极与铂电导电极构成两电极体系，在0 V偏置电压，50 W卤钨灯照射下，考察该体系对H₂O₂的电流响应。实验结果表明该传感器对H₂O₂有良好的传感性能。值得注意的是，这种两电极体系检测H₂O₂，免除了使用参比电极带来的离子污染和操作不便，更有利于实现生物传感器的微型化。实验研究包括以下内容：1.普鲁士蓝修饰n-n⁺-Si光电极对H₂O₂传感性能过氧化氢的无酶传感能克服酶所固有的稳定性不佳、易失活、成本高、在电极表面容易脱落等缺点。基于硅基底研究了一种新型的过氧化氢无酶传感器。采用n-n⁺-Si型硅（111）表面沉积约40 nm厚的金属Pt膜作为基底电极，用循环伏安法在此基底电极上修饰一层晶蓝色普鲁士蓝薄膜后作为光电极，与Pt电导电极构成两电极体系。在0 V偏置电压和50 W卤钨灯照射下，考察了该光电系统对H₂O₂的电流响应，检测限为1.67×10^-6M。对这种新型过氧化氢传感器的工作原理做了初步探讨与分析。实验结果表明该传感器对H₂O₂有优良的传感性能。2.普鲁士蓝/不同金属膜/n-Si型硅H₂O₂的电化学传感抛光的n-Si（111）表面分别真空蒸镀约50 nm厚的Ni、Pt-Ni合金两种不同的金属膜。再分别用循环伏安、恒电位沉积的方法在不同的基体电极上修饰PB，做成两种不同的传感电极。考察了上述两种电极体系对光照和H₂O₂的响应程度。实验结果表明，PB/Ni/n-Si修饰电极对光照有较好响应，且在pH 6.50的磷酸缓冲溶液中对H₂O₂有较好的电催化活性。以PB/Ni/n-Si修饰电极与Pt电导电极构成两电极体系体系，0 V偏压，50 W卤钨灯照射下，该传感器电流随H₂O₂浓度的增大，还原电流在不断的增大，说明对H₂O₂有一定的光电化学响应。3. Pt/n-n⁺-Si电极上化学沉积铁氰化镍（NiHCF）薄膜的H₂O₂传感研究采用简单的化学方法在Pt/n-n⁺-Si基体电极上，沉积铁氰化镍膜作为修饰电极，并对该膜进行了x光电子能谱（XPS）表征。以NiHCF/Pt/n-n⁺-Si修饰电极与Pt电导电极以及饱和甘汞（SCE）构成三电极体系，50 W卤钨灯照射下，在-0.3 V～+0.8V（vs. SCE）范围内，对H₂O₂的电催化有良好的选择性、高的灵敏性和稳定性。以NiHCF/Pt/n-n⁺-Si修饰电极与Pt电导电极构成两极体系，0 V偏置电压，50 W卤钨灯光照条件下，H₂O₂在浓度10^-6M～10^-4M范围内有良好的线性关系，线性方程为y（mA）= 312.2991x + 1.5056（C）（r=0.9992），S/N=3，最低检测限为3.32×10^-6M。结果表明，NiHCF/Pt/n-n⁺-Si修饰电极对H₂O₂有良好的光电化学响应。采用循环伏安和两电极体系计时电流法对n-Si、n-n⁺-Si两种硅基修饰电极对H₂O₂的传感进行了比较。通过实验结果可以看出n-n⁺-Si基底的普鲁士蓝类似物传感器对光照具有良好的响应信号，具有良好的稳定性和重现性。更多还原

【Abstract】 Photo-electrochemical sensor is a new kind of developing analytical devicebased on the photo-electrochemical properties of materials. Because of its remarkablesensitivity, inherent miniaturization, portability and easy integration,photo-electrochemical analysis is becoming a promising analytical technique.Research on the quantitative detection of hydrogen peroxide （H₂O₂） receivedconsiderable attention, because H₂O₂is widely used as an oxidizing agent in chemicaland food industries. It is an essential mediator in food, pharmaceutical, clinical, andenvironmental analysis. Prussian blue （PB, ferric hexacyanoferrate） and its analoguesare the prototype of a number of poly-nuclear transition metal hexacyanometalateshaving an open, zeolite-like structure. PB is usually considered as an“artificialperoxidase”due to its high activity and selectivity toward the reduction of hydrogenperoxide and it has been extensively used in the construction of electrochemicalbiosensors.This thesis mainly investigates three kinds of photoelectrodes based on two kindsof silicon wafers （n-Si and n-n⁺-Si）. About 40 nm three different metals films of Pt, Ni,Pt-Ni alloy were coated onto the front surface of n-Si （111） or n-n⁺-Si wafers in highvacuum evaporating system. Prussian blue （PB） film and nickel hexacyanoferrate（NiHCF） film have been deposited on the surface of metals coated different typessilicon wafer. Cyclic voltammograms and x-ray photoelectron spectroscopy （XPS）were used to characterize the surface of modified electrode. The modified electrodeshave been used for determination of hydrogen peroxide （H₂O₂） with a two-electrodecell in absence of reference electrode by photocurrent measurement at a zero bias butunder irradiation with 50W halogen-tungsten lamp. This work demonstrates thefeasibility of the photo-electrodes, sensitivity of H₂O₂sensors, and provides aneffective approach to detect H₂O₂. Experimental studies include the followingcontent:1. Hydrogen peroxide sensor based on PB modified n-n⁺-Si photo-electrodeA Prussian-blue （PB） film has been deposited on the surface of platinum coatedn-type epitactic silicon （Pt/n-n⁺-Si） wafer. The electro-deposition of PB was achievedby a cyclic scan in a potential range of 0.2 to +0.6 V （vs. SCE） at 50 mV/s for 5cycles in a solution containing 2.5 mM FeCl3, 2.5 mM K3Fe（CN）6, 0.1 M KCl and 0.1 M HCl with an illumination from 50 W bromine-tungsten lamp. The emphasis is laidon that this modified silicon electrodes can be used as sensors for the photocurrentdetermination of hydrogen peroxide only in two-electrode system without referenceelectrode at a zero bias. The use of the PB modified Pt/n-n⁺-Si electrode as ahydrogen peroxide sensor was demonstrated with good stability and selectivity. ThePB film was characterized by cyclic voltammetry measurements and scanningelectronic microscopy （SEM）. A new photo-electrochemical sensor based ontwo-electrode system for determination of hydrogen peroxide has been developed.2. Hydrogen peroxide sensor based on Prussian blue modified and coated withdifferent metals film on the surface of n-Si waferAbout 50 nm two different metals of Ni and Pt-Ni alloy were coated onto the frontsurface of n-Si （111） wafers. The Prussian-blue （PB） film modified Ni/n-Si,Pt-Ni/n-Si electrode was prepared by a simple chemical deposition and cyclicvoltammetry. The PB/Ni-n-Si sensor showed good electro-catalytic activity and goodphotocurrent responses by adding different concentrations of H₂O₂with a definitestability.3. Hydrogen peroxide detection with n-silicon photo-electrodes modified bynickel hexacyanoferrate filmsBy depositing a film of nickel hexacyanoferrate （NiHCF） on platinum film coatedsilicon electrodes, a new photo-electrochemical sensor for the detection of hydrogenperoxide has been developed. The stable film of NiHCF was chemically depositedonto a phosphorus heavy doped silicon （n⁺-Si） with 9μm epitaxial layer （n-n⁺-Si）wafers coated with about 40 nm platinum layer （Pt/n-n⁺-Si）. Cyclic voltammogramsand x-ray photoelectron spectroscopy （XPS） were used to characterize the NiHCFfilm on the Pt/n-n⁺-Si electrode. The NiHCF modified Pt/n-n⁺-Si electrode has beenused for determination of hydrogen peroxide （H₂O₂） with a two-electrode cell inabsence of reference electrode by photocurrent measurement at a zero bias. Thecomposite modified electrode demonstrated good photocurrent responses by addingdifferent concentrations of H₂O₂with a definite stability. The modified electrode wasused as a sensor for H₂O₂, with a linear range from 3.3×10 6to 1.0×10^-4M of H₂O₂,with a detection limit （S/N = 3） of 3.3×10^-6M and with a sensitivity of 42 mA M 1cm 2. This provides a facile way of detecting H₂O₂and succeeds in averting frominconvenient reference electrode.更多还原