光阴极用多壳层中空微球的可控制备及光助微生物燃料电池的构建

Microbial fuel cells (MFCs) as the novel renewable energy hold great promises to address the two major global problems (energy crisis and environmental pollution) simultaneously. The photo-assisted MFC is a new direction of development of MFC, because the photocathode materials are considered as potential alternatives to traditional cathode catalysts. The preparation of unique photocathode material will be the key to achieve this goal. In this project, we propose a new concept of Template Multi-stage Pyrolysis in the porous microspheres to prepare the multishelled hollow microspheres (MHMs) as the photocathode. And their preparation process,the law of the shell formation and growth, the mechanism of template pyrolysis in the process will be studied. A controllable and predictable preparation process will be achieved by developing a simple mathematical model to explain the mechanism of multi-stage thermal decomposition. Applying the above method, the p-type ZnO MHMs, with favorable band structures for coupling microbial electron transfer and proton reduction aforementioned, will be synthesized and used as photocathode. We will further explore the internal mechanism of the structure of p-type ZnO MHMs for enhanced light absorption, photoelectric conversion, oxygen adsorption and reaction on the photocathode. Finally, the concept the photo-assisted MFC will be demonstrated, and the p-type ZnO MHMs photocathode and the bioanode function synergistically to combine the energy from solar light and organic substrate for driving microbial electricity generation, increasing the electron transfer and output power. The photoelectrochemical process, the mechanism of electron transfer and biochemical reactions will be revealed in the novel photo-assisted MFC. We hope to provide the important experimental and theoretical basis for the design and preparation of new generation of photo-assisted MFC.

微生物燃料电池是解决日益严峻的能源和环境问题的绿色能源。光助微生物燃料电池采用光伏效应替代传统的阴极催化剂作用，是微生物燃料电池发展的新动向。制备结构独特的光阴极材料是实现这一目标的关键。本项目提出一种"模板多级热解法"制备光阴极用多壳层中空微球的新方法，研究其制备工艺及形成过程中的壳层生长与模板热解规律，阐明均匀多壳层空心微球模板多级热解机理，建立简单的数学模型，使制备过程更加可控和可预测化。并采用该方法制备的p型ZnO多壳层中空微球作为光阴极材料，借助该材料的带隙匹配和多级结构对光的利用与载流子传输的研究，探讨光阴极对光吸收、光电转换和氧气吸附反应的匹配与优化。最后构筑光助微生物燃料电池，利用太阳能转化为电能，同时促进微生物的反应，提高电池的电子传递和输出功率，探讨该电池的光电化学过程、电子传递和反应物转移的机理，为设计和制备新一代光助微生物燃料电池提供理论依据。

基于半导体的光电化学体系可应用于光助燃料电池体系以提高燃料电池诸如功率密度、开路电压等性能。偶合细菌和酶等生物质，可进一步优化燃料电池的器件性能。本课题以探索了基于宽禁带半导体（如TiO¬2）和窄禁带的半导体材料（如CuInS2）作为微生物/生物质燃料电池的光电极材料为基础工作，同时利用模板法等途径，构建了多级纳米结构的燃料电池氧还原催化剂。研究成果为燃料电池催化剂的开发以及其他电化学能源转化材料的可控制备提供了思路。本课题重点开展了下列研究：（1）研究了CdS量子点敏化TiO2电极作为光阳极在光助生物燃料电池的应用，揭示了葡萄糖作为生物质燃料对电池性能的影响；（2）制备了新颖的CuInS2 纳米花结构，探讨了其作为光助微生物燃料电池和光电化学生物传感器的功能性。探讨了CuInS2光激发过程对电池性能的提高，且所制备的光电化学生物传感器具有较低的检测限、迅速的响应、较宽的检测范围、较好的选择性和抗干扰性；（3）研究了模板法制备碳基非贵金属燃料电池阴极氧还原催化剂，重点探讨了非金属掺杂、过渡金属纳米结构与碳基体相互作用对氧还原电极动力学的提高，在实现廉价氧还原催化剂方面具有指导意义；（4）基于原位反应方法，制备了过渡金属基石墨烯复合物，通过构建多级电极结构，结合石墨烯的高电导性和过渡金属基化合物的高比容量，以达到提高锂离子电池负极材料容量、倍率性能、循环性能等性能参数。（5）尝试了以模板法、氢键自组装、静电自组装等方法将不同功能性的微纳米单元结构有效复合，构建多功能、形貌可控的纳米阵列、多组分微球等体系，用于重要的光谱分析、电化学检测、湿法催化、水污染处理等重要用途。