高效原位电催化氧还原合成双氧水电极材料的制备及性能研究

The in-situ synthesis of H2O2 through the electrocatalytic reaction of oxygen reduction has received a great deal of attention due to its advantages such as environmental benign, low energy consumption, and simplicity in system. The key to its development and real application lies on the research and development of efficient electrocatalysts. The present proposal aims to synthesize novel PdAu@CeO2/C composite catalysts to enhance the activity and selectivity for H2O2 generation through the electrocatalytic reaction of oxygen reduction , by taking advantage of the decreased ability for H2O2 decomposition by acid treatment of carbon support, the storage and enrichment capability for oxygen of CeO2, and high activity and selectivity of PdAu towards H2O2 generation as well as their intrinsic stability. This project includes the following main investigations: supporting CeO2 onto the acid treated carbon materials by microwave decomposition method, and then with them as the support, synthesizing PdAu by combining the multistep microwave assisted polyol method and alloying post-treatment process; revealing the key parameters for preparing the highly efficient electrocatalysts for H2O2 synthesis through oxygen reduction reaction by systematically investigating the relationship between the components and structure of PdAu@CeO2/C and its corresponding electrochemical performance under different operation modes; and then, based on the above results, exploring for the synergetic effect of different components in the catalyst and clarifying the corresponding electrocatalytic mechanism. Through this project, it is expected to provide both key material and technical support for the on-site, environmentally friendly, and economical technology for H2O2 synthesis.

原位电催化氧还原合成H2O2技术由于其绿色、低能耗、装置简单等优点近年来倍受关注，其发展和实际应用的瓶颈在于高效电催化剂的研发。本项目旨在利用炭载体酸化处理降低H2O2分解的特征、CeO2的储氧和富氧能力、及PdAu合金催化氧还原生成H2O2的高活性和高选择性及贵金属的稳定性，研制新型PdAu@CeO2/C复合电催化剂，以期提高电催化氧还原合成H2O2的活性和选择性。研究内容包括采用微波分解法在酸处理后的炭载体上负载CeO2；进而联用分步微波辅助多元醇还原技术和合金化后处理过程制备其负载的PdAu催化剂。通过关联PdAu@CeO2/C组成、结构与不同操作模式下电催化氧还原合成H2O2电化学性能的关系，揭示制备高效氧还原合成H2O2电催化剂的关键因素；在此基础上，探索各组分之间的协同作用和阐明催化机理。本项目成果为H2O2原位、绿色、经济的合成技术提供关键材料支撑和技术支持。

高效电催化剂的研发已成为电催化2e-氧还原反应（ORR）制备H2O2技术发展的瓶颈。本项目首先选用廉价非金属碳基材料-多壁碳纳米管为基体，采用浓硫酸高锰酸钾氧化技术，精准调控多壁碳纳米管的结构和组分，获得了管壁外层被破坏而内层结构得到部分氧化的碳纳米管粉体，其电催化2e ORR合成H2O2的性能大幅度提高；其次，考虑到自支撑、一体化电极电催化2e ORR制备H2O2制备工艺较粉体催化剂更简便、应用前景更广阔，我们选取三维活性面积高、化学稳定性好、导电性高的石墨毡作为一体化电极，创新利用高温环境下乙酸蒸气的强刻蚀性，在石墨毡纤维上原位引入缺陷和含氧官能团，实现了适量缺陷修饰的石墨毡一体化电极的高效、稳定电催化2e ORR原位制备H2O2；再次，考虑到新型能源一体化系统能够加强各种新能源转换技术之间的取长补短和融合，进而为高效、清洁、可持续能源的实际应用提供新思路和可行的解决方案，我们采用“硬模板-水热-高温炭化”技术，制备高度有序、高活性、高2e-选择性的介孔炭，一方面以增强氧还原制双氧水的性能；另一方面通过对上述介孔炭进行氮掺杂以促进高4e-ORR选择性用于锌-空气电池。将上述催化剂与锌-空气电池电极耦合，成功构筑锌-空气电池-氧还原合成双氧水-污水处理一体化系统，将锌-空气电池输出的电能自驱动电化学还原原位合成双氧水，同时利用合成的双氧水原位降解污水处理中污染物RhB。2 h内的RhB去除效率几乎达到100%。这种新型一体化系统为新能源转换和污水处理联合应用提供新概念。最后，考虑到通过光增强的电催化能够进一步提高化学反应动力学，我们开发了具有可见光响应的一体化电极并高效用于光电催化2e ORR原位制备H2O2，在此基础上，设计并构筑了“光增强锌-空气电池-光电催化2e ORR原位制备H2O2-污水处理”多功能器件联用一体化系统，为设计基于光电催化的器件-反应-应用耦合的多功能、一体化系统提供新思路。. 通过本项目的实施，完成了研究计划。已发表期刊论文16篇，会议论文10篇；授权专利2件、申请专利2件；培养博士生1名，硕士生5名、本科生1名；赴国外进行学术交流3人次。