富氧空位Zn2+掺杂的纳米多孔Co3O4纳米片阵列的析氧性能研究

Co3O4, with its high activity and stability, has been intensely investigated as a promising oxygen evolution reaction (OER) catalyst in alkaline water splitting. Nonetheless, the kinetics of the OER is sluggish, which requires a large overpotential to driven water oxidation. Thus, extensive efforts and approaches have been taken to enhance OER performances, such as introducing oxygen vacancies, improving the electronic conductivity, doping specific exotic metal atoms, constructing superaerophobic surfaces and enhancing the specific and electrochemically-active surface areas. However, no works to incorporate all of the five approaches together. In our previous work, we have synthesized hierarchical Zn-doped Co3O4 array and investigated their OER activity. The results show that the electroactivity can be achieved by optimized chemical environments for Co ions and construction of hierarchical arrays. In this regard, we are motivated to adopt an engineering strategy integrating the above five approaches together to obtain Zn-doping Co3O4 nanosheets array with rich in oxygen vacancies and highly nanoporous structure. The relationships between the adsorption of OH-, electronic conductivity, the chemical/physical desorption of O2 from catalyst, porous structure and catalytic activity will be clearly discussed. In particular, we focus on study of the regulatory mechanism that arising from the doping and oxygen vacancies. Furthermore, based on the interfacial properties and dynamic barrier, this project intends to establish a deep relationship between the catalyst microstructure and OER performance, and thus provide guidelines for the future design of desirable OER catalyst and to advance the understanding of the OER mechanism.

Co3O4对析氧反应（OER）具有高的催化活性和优良的稳定性，其在碱性电解水领域的应用已受到广泛关注。但OER催化中缓慢的动力学使得该反应需要较高的过电势。研究表明引入缺陷位、改善导电性、掺杂过渡金属、构筑超疏气界面和增大比表面能有效调控和提高Co3O4的OER催化性能，但同时集成这五种手段的研究尚无报道。本项目计划在前期研究的Zn2+掺杂Co3O4多级纳米结构阵列的基础上，发展集成上述五种改性方法的纳米工程化手段，制备富氧空位Zn2+掺杂的纳米多孔Co3O4纳米片阵列，进一步降低Co3O4的析氧过电势；探究表面氢氧根吸附、电子转移、氧气脱附、气泡粘附和多孔结构对OER的影响；阐明元素掺杂和氧空位协同调控OER的作用机制。从界面性质和表面反应势垒变化入手，建立材料微结构与OER性能之间的内在关联性。上述研究将深化对OER催化机理及其制约因素的认识，为非贵金属OER催化剂的设计提供新的思路。

电解水制氢是应对能源短缺和环境污染的一种有效的解决途径。该反应可分为析氢反应和析氧反应两个半反应。然而，受限于析氧反应缓慢的四电子转移过程，它已成为制约电解水技术发展的瓶颈。因此，设计和合成高性能的析氧催化剂是提高电解水效率的关键。传统的贵金属氧化物催化剂，尽管活性高，但由于价格昂贵且储量有限阻碍着其商业化推广。近年来，Co3O4由于其在碱性环境中表现出高的析氧活性和良好的稳定性而受到人们的广泛关注。不过，该类材料也存在着电子传导能力差、活性比表面小、反应位点暴露不充分、气体产物不易脱附等问题，故要实现Co3O4的规模化应用，仍需要从结构和组分上对其进一步优化。.本项目利用纳米工程化手段制备了富氧空位Zn2+掺杂的纳米多孔Co3O4纳米片阵列；详细考察了表面氢氧根吸附、电子转移、氧气脱附、气泡粘附和多孔结构对OER的影响，以此指导和优化合成和后处理方法；结合理论计算与实验研究阐明元素掺杂和氧空位协同调控OER的作用机制。从界面性质和表面反应势垒变化入手，建立材料微结构与OER催化性能之间的内在关联性，并构筑两者的关系模型，深化对钴基氧化物OER催化机理的认识，为碱性电解水体系OER催化剂的功能导向性设计与性能优化提供一定的指导性发现。