基于不锈钢网柔性基底高效氧化锌光阳极的制备及其光电化学制氢性能研究

Due to the energy crisis and environmental pollution, hydrogen production by water splitting has attracted much attention in recent years. In the process of hydrogen production by water splitting, the electrochemical decomposition of water based on the electrochemical reaction of semiconductor electrolyte interface has been widely studied because of its low cost and environmental friendliness. However, its conversion efficiency for water spliting is still low due to the two obstacles: (1) the poor absoption of light in visible region due to a larger bandgap, which can only absobed mainly in the UV range;(2) fast recombination of electron-hole pairs, which result in the low carrier collection efficiency. The scopes of this project are: Fistly, we propose synthes of ZnO nanowire array with large specific surface area on SSM which was utilized as a "high speed electronic channel” for photoanode nanostructure of efficient PEC water splitting devices. And then, two main strategies have been developed to increase the light harvesting in visible range, including doping with metal or nonmetal elements and sensitizing with narrow-bandgap semiconductor quantum dots. The successful implementation of this project will provide a feasible route for the breakthrough of Photoelectrochemical hydrogen production efficiency.

由于能源危机和环境污染，使得光解水制氢近年来备受关注。在各种光解水制氢技术中，基于半导体电解液界面电化学反应的光电化学分解水制氢由于成本较低、环境友好而受到广泛研究。但是已报道的光解水制氢效率一直较低，主要归结于：（1）半导体能带较宽使得其不能吸收可见光，仅能利用紫外光；（2）电子空穴复合速率较快，使载流子收集效率较低。本项目针对这一问题，提出了一种基于ZnO纳米线阵列的“高速电子通道”的高光解水制氢性能的光阳极结构。首先，选用不锈钢网作为导电基底制备大比表面积的三维ZnO纳米线阵列网络，作为高速电子通道；然后，通过元素掺杂和量子点敏化两个方面协同作用进一步增加光阳极的可见光吸收能力，最终获得优异的光解水制氢性能。本项目的顺利实施将为光电化学制氢效率的突破提供一个可行的路线，有助于推动光电化学制氢的实际应用。

氢作为一种高能燃料，将会作为清洁能源应用于社会多个领域。本项目利用水热法在不锈钢网上均匀制备了ZnO纳米线阵列，研究了不锈钢网基底目数、生长时间、退火温度、氨水浓度等对ZnO纳米线阵列形貌、结构和光电化学性能的影响。对于平纹编织的不锈钢网，光电化学性能随着不锈钢网目数的增加而提高。退火处理可以显著改善ZnO光阳极的光电化学性能。本项目进一步用CdS对ZnO纳米线阵列进行改性，CdS敏化后的ZnO纳米线阵列基光阳极具有以下优点：可见光区域有很强的吸收、为载流子提供高速通道、低的电子-空穴复合率。通过对敏化次数的优化研究，敏化15次的ZnO光阳极的获得最大的光电流密度和产氢率，较纯的ZnO纳米线阵列的电流密度显著提高。为了进一步增大比表面积，本项目制备了具有次级结构ZnO纳米线阵列，次级结构ZnO纳米线阵列在CdS敏化7次时光电流密度达到最大。本项目进一步通过TiO2包覆改善ZnO的化学腐蚀和光腐蚀问题，使稳定性得到改善。以不锈钢网为基底生长ZnO纳米线对于光电化学分解水制氢是非常有效的光阳极结构。