基于表面终结态精细调控构筑高效非金属碳基薄膜氧电极催化剂的研究

It is crucial and urgent to find alternative catalysts for fuel cells and metal-air batteries, aiming at replacing noble metal catalysts. It has been demonstrated that heterogeneous carbon materials show similar activity for the oxygen electrode reaction (ORR and OER). However, it is quite controversial for pinpointing the origin of active sites in doped carbon materials. Moreover, a comprehensive study is lack for optimizing the catalytic activity of oxygen electrode by tuning the fine surface termination state. Based on our previous theoretical and experimental investigations, this project targets to govern and control the surface structure of heteroatoms doped carbon film by a variety of treatments at the mesoscopic/microscopic/atomic scales. The doped atoms and groups on the surface will be identified by using EELS and low-voltage Cs-corrected electron microscopy as well as XPS and AES. Furthermore, complemented with in-situ XAS, Raman and first-principles calculation, the accurate surface termination states will be clarified, the catalytically active sites for ORR and OER will be revealed, and the architecture style of active sites of surface will be explored. The knowledge will be updated for surface structure of carbon-based catalyst for oxygen electrode on an unprecedented atomic/molecular level. Thus, we can provide guidance to design and prepare practical carbon-based catalysts abundant with concerted catalytically surface active sites.

寻求贵金属催化剂的替代材料是燃料电池与金属-空气电池等新能源领域前沿和热点问题之一。已有研究表明，非金属掺杂碳材料作为氧还原反应(ORR)与氧析出反应(OER)的催化剂具有与贵金属可比拟的催化特性。然而，科学界对掺杂碳材料氧电极反应催化活性来源众说纷纭。针对表面终结态的精准调控，优化氧电极催化活性，有效解决上述科学问题的系统性研究鲜有报道。基于申请人前期的理论与实验研究，本项目拟通过多方面的手段对碳膜的表面结构进行介观、微观及原子水平上的精准调控。采用电子能量损失谱和低电压球差校正电镜辅以XPS、AES等，辨认表面暴露的掺杂原子及基团，结合原位XAS、Raman等及第一原理计算，对碳膜的表面结构进行精准表征，揭示ORR/OER的催化活性位，探寻构建表面活性位的有效方法，将对碳基氧电极催化剂表面结构的认知提升到原子水平，为设计和制备表面富含协同催化活性位点、可实用化碳基催化剂提供指导。

寻求贵金属催化剂的替代材料是燃料电池与金属-空气电池等新能源领域前沿和热点问题之一。通过极其微量的杂原子（过渡金属、非金属）掺杂碳材料作为氧还原反应(ORR)的催化剂具有与贵金属可比拟的催化特性。然而，科学界对掺杂碳材料氧电极反应催化活性来源众说纷纭。针对表面终结态的精准调控，优化氧电极催化活性，有效解决上述科学问题的系统性研究鲜有报道。基于申请人前期的理论与实验研究，本项目通过设计多种不同制备策略，在微观尺度及原子水平上实现碳基催化剂的表面状态的精细调控。采用电子能量损失谱和球差校正电镜辅以XPS等，辨认表面暴露的掺杂原子及基团，结合原位XAS、Raman等表征技术及第一原理计算，对碳基催化剂的表面终结态和价态信息进行了精准表征，揭示了ORR的催化活性位，并对面向氧析出反应(OER)/氢析出反应(HER)的相关催化剂的活性进行了精准表征，提出了构建表面活性位的有效方法。相关研究成果经整理总结后，在国际学术期刊上发表20余篇论文，并参加学术会议交流10余次。因此对碳基氧电极催化剂表面结构的认知提升到原子水平，为设计和制备表面富含协同催化活性位点、可实用化碳基催化剂提供指导。