【作者】 顾永娥；

【导师】 王春明； Joseph Wang；

【作者基本信息】 兰州大学 ， 分析化学， 2013， 博士

【摘要】 本博士学位论文主要分为纳米Cu2O及其修饰电极的制备、光电催化降解中间产物电分析应用,和以植物组织为基础的酶燃料电池、纳米马达的研究两大部分。首先在新体系Cu(Ⅱ)-柠檬酸溶液中分别研究了用脉冲电沉积法和液相还原法制备纳米Cu2O。利用粉末X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和X射线光电子能谱(XPS)等手段对产品的结构、成分、尺寸及形态进行了表征,开关灯开路电位实验考察了Cu2O的光电化学性质。旋转环盘电极(RRDE)法研究了Cu2O纳米粒子修饰电极对对硝基苯酚(pNP)的光电催化降解中间产物的分析应用性能。此外,我们还开发了用香蕉果肉制作的酶燃料电池和马铃薯组织的纳米马达。论文主要内容如下：1.花状Cu2O纳米粒子的制备及其电催化性能研究采用脉冲电沉积技术,在Cu(Ⅱ)-柠檬酸电解质溶液中制备了高度分散的花状Cu2O纳米粒子。扫描电子显微镜形貌(SEM)分析显示花状Cu2O粒子的成因是Cu2O(111)沿着立方Cu2O(100)方向连续生长所致。用XRD和XPS对沉积物的结构及化学组成进行了分析。用紫外/可见-漫反射(UV/Vis-DRS)光谱技术研究了Cu2O的光学性能和禁带宽度。开关灯不同条件下的开路电位～时间技术研究表明花状Cu2O纳米粒子具有明显的p-型半导体光电性质；循环伏安法(CV)实验研究证明所制备的花状纳米Cu20对对硝基苯酚(pNP)有明显的电催化作用。2.Cu2O纳米粒子修饰的旋转环盘电极(RRDE)对对硝基苯酚(pNP)的光电催化降解行为研究在非模板法水合肼(N2H4·H2O)还原Cu(Ⅱ)-柠檬酸络合物制备Cu20纳米粒子的基础上,将所得纳米Cu2O修饰于Pt-RRDE盘电极上(盘、环电极均为Pt材质),然后采用动力学差示脉冲伏安(HDPV)技术原位检测了pNP在可见光照射下的光电化学行为。实验证明了pNP在Nano-Cu2O修饰的盘电极上首先经历光电催化降解、产生电活性的对羟胺基苯酚,然后该对羟胺基苯酚被强制对流传质输送到Pt环电极表面,从而在0.05V处检测到其氧化信号。以此信号为基础建立了对pNP的电催化测定方法。在优化的条件下电催化测定pNP,氧化峰电流与pNP的浓度在1.0×10-5～1.0×10-3M范围内呈线性关系,检测限为1.0×10-7M。连续测定10次5.0×10-5MpNP的相对标准偏差(RSD)为2.8%。3.Cu2O纳米空心球、纳米片和八面体的非模板法制备及形貌关联的半导体性能分析通过微调溶液pH值的方法,柠檬酸铜盐配合体系中水热合成了不同形貌的纳米Cu2O(空心球、薄片和八面体形状)。用XRD.SEM和HRTEM对所得纳米Cu2O的晶体结构和形貌进行了表征。这种微调溶液pH值控制形成不同形貌的机理与奥氏熟化有关。光电化学实验表明在pH8-11范围内形成的Cu2O空心结构显示n-型半导体特性。相对地,在更碱性条件下(如pH大于或等于12)形成的实心的Cu2O八面体具有p-型半导体性能。4.以植物组织电极为基础的高效酶生物燃料电池香蕉组织富含多酚氧化酶(PPO),这种酶能够还原氧气为水,可用作生物燃料电池的阴极催化剂,我们以此为基础证明了第一个以葡萄糖脱氢酶(GDH)为阳极,香蕉修饰的碳糊电极为阴极的葡萄糖燃料电池。梅尔多拉蓝(MDB)用作阳极GDH的电子传递物质,而香蕉组织内酚类成分作为生物阴极PPO的电子传递物质。以香蕉组织为基础的生物燃料电池的最大输出功率和开路电压分别为57μW/cm2与0.46V。与纯酪氨酸酶(Tyr)制作的生物阴极相对比,香蕉组织为基础的燃料电池每单位成本的输出功率提高了9354倍(166502μW/＄vs.17.8μW/＄)。此香蕉生物燃料电池的寿命可达2周以上。我们并且提出并证明了构建以发芽的番茄种子为阳极,香蕉电极为阴极的纯天然不需外加燃料的生物燃料电池的设想。发芽的番茄种子含有乙醇脱氢酶(ADH),NAD+和乙醇,将番茄种子的碳糊电极作为生物阳极(bioanode)与香蕉生物阴极(biocathode)相组合。5.自推进化学驱动的植物组织生物马达描述了以植物组织为基础的自推进式生物催化马达,分别制备了马铃薯、胡萝卜组织和小米粒的小马达。此组织马达依赖于它们自身丰富的过氧化氢酶的活性,可催化分解过氧化氢燃料并产生气泡的推力。与以纯酶(过氧化氢酶)修饰制备的生物马达相比,这种天然的生物马达不需要进行酶的修饰,具有很好的生物兼容性且成本低廉,寿命长并表现出可观的运动速度和操作稳定性。更多还原

【Abstract】 In this thesis, it includes the fabrication of Cu2O and its modified electrodes, photoelectrocatalytic degradation intermediates electroanalytic application, and the plant tissue based biofuel cells and nanomotors. Nano-CU2O were fabricated from new system Cu (Ⅱ)-citrate using pulsed electrodeposition and solution reduction method, respectively. The structures, compositions, sizes and morphologies were characterized by using some techniques such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The photoelectrochemical properties of CU2O were characterized by light switch open circuit potential (OPC-t) experiments. The photoelectrocatalytic performance of Cu2O nanoparticles for p-nitrophenol (pNP) was studied using rotating ring-disk electrode (RRDE). In addition, the plant tissue based biofuel cells made with banana pulp and potato tissue micromotors were developed. The main contents are as follows:1. Preparation of flower-like Cu2O nanoparticles and their electrocatalytic applicationPulsed electrodeposition technique was employed for preparation of highly dispersed flower-like CU2O nanoparticles from Cu (Ⅱ)-citrate solution. The morphology analysis of the particles using SEM reveals that the flower-like particles were from sequential growth of Cu2O along the (111) direction on the cubic Cu2O (100). The structure and the chemical composition of the deposits were characterized by XRD and XPS. Optical property and band gap of the Cu2O was investigated using UV/vis diffuse reflection spectra (DRS). The dark and light open circuit potential-time characterization study showed that the flower-like Cu2O nanoparticles exhibited good photoelectric response. Cyclic voltammetry carried out in the presence of p-nitrophenol (pNP) shows that the electrocatalytic performance of the CU2O particles for the reduction of pNP. The influence of the incidence of light on the electrocatalysis is also discussed.2. Investigation of photoelectrocatalytic degration behavior of Cu2O nanoparticles for pNP using Cu2O modified RRDE Cu2O nanoparticles were obtained by reducing the copper-citrate complex with hydrazine hydrate (NaH4·H2O) in a template-free process. A Cu2O nanoparticles modified Pt RRDE was successfully fabricated, the hydrodynamic differential pulse voltammetry (HDPV) technique was applied for in situ monitor the photoelectrochemical behavior of pNP under visible light. pNP undergoes photoelectrocatalytic degradation on nano-Cu2O modified disk to give electroactive p-hydroxylamino phenol species which is compulsive transported and can only be detected at ring electrode at around0.05V with oxidation signal. This signal can be used for the electrocatalytic determination of pNP. The effects of illumination time, applied bias potential, rotation rates and pH of the reaction medium have been discussed. Under optimized conditions for electrocatalytic determination, the anodic current is linear with pNP concentration in the range of1.0×10-5to1.0×10-3M, with a detection limit of1.0×10-7M and good precision (RSD=2.8%, n=10).3. Template-free Fabrication of Nano-sized Cu2O Hollow Spheres, Sheets and Octahedrons and their Morphology-dependent Semiconductor TypeNano-sized cuprous oxide (Nano-Cu2O) materials with different morphologies such as hollow spheres, two-dimensional (2D) sheets and octahedrons were synthesized using a simple hydrothermal method in a Cu-citrate complex solution by making small adjustments to the solution’s pH value under alkaline conditions. The morphology and crystalline features of the Cu2O was observed using XRD, SEM and HRTEM. The formation mechanism is associated with localized Ostwald ripening. The photoelectrochemical experiments showed that the hollow Cu2O structure synthesized under a pH range of8-11exhibited n-type semiconductor characteristics. Alternatively, solid octahedral Cu2O formed in the presence of strong alkaline conditions (i.e. pH greater than or equal to12) and exhibited p-type behavior.4. High-Power Low-Cost Plant Tissue-Based Biofuel CellThe banana tissue rich with polyphenol oxidase (PPO), an enzyme able to reduce oxygen to water, which can be used as catalyst for the biocathode. We demonstrate the first example of using plant tissues for the operation of biofuel cells (BFC), the banana modified carbon paste electrode as biocathode and glucose dehydrogenase (GDH) as bioanode. Meldola’s blue (MDB) were used as anode mediator, while the phenolic constituents of the banana serve as mediator for PPO. The maximum power output and open circuit voltage (OCV) of the banana-based tissue biofuel cell were57μW/cm2and0.46V, respectively. Cost analysis of this tissue biofuel cell system indicates dramatic improvements in terms of the power-output/dollar compared to the use of pure enzyme tryosinase (166502μW/＄vs.17.8μW/＄, i.e.,9354times improvement). The banana-based biofuel cell displayed an extended lifetime of over2weeks. We also demonstrate a fuel-free full plant-tissue based BFC concept, combining the banana biocathode with a bioanode based on germinated tomato-seeds that contain alcohol dehydrogenase (ADH), NAD+and ethanol.5. Self-propelled chemically-powered plant-tissue biomotorsSelf-propelled biocatalytic motors based on plant tissues are described. The potato, carrots and millet motors were developed. The tissue motors rely on their rich catalase activity towards biocatalytic decomposition of the H2O2fuel and generation of the bubble thrust. Compared with the pure enzyme (catalase) biomotors, these biomotors obviate the need for pure enzymes, and offer a remarkably low cost, good lifetime, good biocompatibility and thermostability.更多还原