【作者】 王娟；

【导师】 张伟德；

【作者基本信息】 华南理工大学 ， 应用化学， 2014， 博士

【摘要】 光电化学过程中，光电转换效率主要由光电极决定。光电极材料形貌、结构的调控，对电极光电化学性能的提高起到重要的作用。开发化学性能稳定、对光的利用率高、光电转换效率高的电极材料是光电转换技术的重点。低维纳米材料和具分级结构的纳米材料，其独特的形貌和结构，能产生优异的电学、光学性质，在光电化学和电化学领域具有广阔的应用前景。单一光解水产氢材料自身光生电子空穴对易复合，光电转换效率较低。本论文中，我们合成一维有序阵列结构和具分级结构的半导体光电极材料，通过对材料的形貌、结构进行调控，同时对材料进行复合改性，开发具有优异光电化学性能的光电极复合材料。本论文的主要内容归纳如下：1.利用水热法在FTO衬底上制备了TiO2纳米棒阵列薄膜（TiO2NRs/FTO）。然后，于半封闭反应器中用热缩聚法，将具有可见光响应的类石墨氮化碳颗粒修饰到TiO2NRs/FTO表层。随后对复合材料的光电化学性能进行了研究。实验结果表明，与TiO2NRs/FTO相比，经类石墨氮化碳颗粒修饰后，扩展了材料对光的响应范围至可见光区，一维的阵列结构为电子的传输提供了直接的路径，复合材料的协同作用，抑制了光生电子和空穴的复合，提高了材料的光电化学性能和光电催化降解有机污染物的性能。2.利用两步电化学沉积法，在FTO衬底上制备了ZnO纳米管阵列薄膜（ZnONTs/FTO）。在前面的工作的基础上，将具有可见光响应的类石墨氮化碳颗粒热缩聚填充ZnO纳米管和管之间的空隙，或是沉积到ZnO纳米管内。以期让两者有更多的接触位点，实验结果表明，两者复合后，复合物的平带电势负移，载流子密度增大，抑制电子空穴对的复合，在沿ZnO纳米管传输时的复合，提高光电化学性能。3.通过水热氧化过程在铜片上合成了氧化铜纳米片；然后，通过表面刻蚀、成核、水热生长三步法，合成了分级结构的ZnO纳米花/CuO纳米片（ZnO NFs/CuO NPs）。考察了分级结构复合材料的光电化学性能，发现复合后，光电流响应和光电转换效率都提高了数倍，光电化学性能的提高主要归因于两种材料间的协同作用，抑制了光生电子空穴对的复合，同时分级结构能吸收更多可见光，为电子的传输提供了有效路径。4.合成了ZnO/CuxO核壳分级结构（ZnO shell/CuxO core）复合材料。首先用水热法，在铜片上合成了氧化铜纳米线，然后，以CuxO纳米线为生长位点，合成了ZnO纳米线包覆的CuxO核壳结构，即ZnO shell/CuxO core复合材料。实验结果表明，和单一材料相比，复合材料的光电化学性能得到极大提高。CuxO和ZnO的协同作用，及核壳分级结构ZnO的纳米线为电子传输提供的多重有效路径，光生电子-空穴对的有效分离，从而提高复合材料光电化学性能。5.采用一步水热法，在金属铜片上制备了CuO纳米片电极，构筑无酶型葡萄糖传感器。该传感器具有良好的选择性、稳定性、较高的灵敏度和抗其它小分子干扰的能力，实现了对葡萄糖含量的快速便捷检测。更多还原

【Abstract】 In the PEC process, the solar conversion efficiency is mainly determined by thephotoelectrodes. Morphological and structural control of photoelectrode play an importantrole for enhancement of PEC properties.The development of photoelectrodes with high utilization of solar energy, high energyconversion efficiency and excellent stability is the key issue for PEC technology. Owing totheir unique morphologies and structure, low dimensional nanomaterials or nanocompositewith hierarchical structures, have been widely applied in photo-electrochemistry andelectrochemistry. The rapid recombination of photoinduced electrons and holes greatly limitsthe quantum efficiency of single photoelectrode matrial. In this dissertation, our work focusedon the synthesis of one dimensional, well organized arrays of semiconductive nanomaterials.We intend to improve the PEC properties of photoelectrode material by morphological andstructural control of photoelectrode matrials, as well as combination of two differentmaterials.The details are summerized briefly as follows:1. Firstly, TiO2nanorod arrays on FTO substrate were synthesized by hydrothermalprocess. After that, a facile thermal polycondensation process in half closed reactor wasconducted for the deposition of g-C3N4nanoparticles onto TiO2nanorod arrays. PECmeasurements were proformed with the g-C3N4/TiO2NRs nanocomposites. The experimentresults indicate that, after introducing g-C3N4, the absorption spectrum of the composite isexpanded to visible region of solar spectrum, the flat band shifted to a more negativepotential, and the donor density was also greatly increased. The one dimensional structureprovided direct path way for the transfer of electrons. Thus, the recombination ofphoto-induced electrons and holes was hindered, the PEC properties were greatly enhanced.2. ZnO nanotube arrays on FTO substrate were prepared by two-step electrochemicalprocesses. And then, g-C3N4nanoparticles were deposited into the interspaces of the ZnOnanotube arrays or into the inner wall of the ZnO nanotubes to provide more contact sites forZnO and g-C3N4. After coupling of ZnO nanotube arrays and g-C3N4, the flat band shifted toa more negative potential, and the donor density was also greatly increased. The one dimensional structure provided direct path way for electrons transfer, so the recombination ofphoto-induced electrons and holes was hindered, thus greatly enhanced the PEC properties.3. CuO nanoplatelets were synthesized on Cu substrate by a hydrothermal oxidationprocess, and then ZnO nanoflowers were grown on the CuO nanoplatelets by a three-stepprocedure consisting of etching, seed nucleation and hydrothermal growth. Theelectrochemical properties and photoelectrochemical properties of the ZnO/CuO areinvestigated. The PEC properties were greatly enhanced under visible light irradiation. This isattributed to the large contact area with the electrolyte and high conductive pathway forcharge carrier collection of the nanocomposite as well as the synergistic effect between thetwo components. The ZnO/CuO nanocomposite holds great potential for application for solarenergy conversion.4. Hierarchically branched ZnO/CuxO heterostructure was fabricated through a simplewet chemical method combined with a hydrothermal process. Under visible light irradiation,hierarchically branched ZnO/CuxO photoelectrode showed enhanced PEC properties. Theadhesive growth of ZnO nanowires on the CuxO backbones greatly improves the exposedsurface area, and the one-dimensional ZnO nanowires continuously provide conductivepathways for the transfer of photo-induced electron.5. The CuO nanoplatelets were fabricated on Cu foil by a one-step hydrothermal process.The attached growth of CuO nanoplatelets on Cu foil is easy to be integrated as an electrodefor enzyme-free sensing of glucose. An excellent selectivity, good stability, high sensitivityand anti-interference property was obtained, and the facile and quick determination ofglucose concentration is realized.更多还原