Pang Ruichao, Tian Pengfei, Jiang Hongliang, Zhu Minghui, Su Xiaozhi, Wang Yu, Yang Xiaoling, Zhu Yihua, Song Li, Li Chunzhong
Key Laboratory for Ultrafine Materials of Ministry of Education, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
Natl Sci Rev. 2020 Aug 24;8(7):nwaa187. doi: 10.1093/nsr/nwaa187. eCollection 2021 Jul.
Unveiling the structural evolution and working mechanism of catalysts under realistic operating conditions is crucial for the design of efficient electrocatalysts for CO electroreduction, yet remains highly challenging. Here, by virtue of structural measurements at multiscale levels, it is identified under CO electroreduction conditions that an as-prepared CeO/BiOCl precatalyst gradually evolves into CeO/Bi interface structure with enriched Ce species, which serves as the real catalytically active phase. The derived CeO/Bi interface structure compared to pure Bi counterpart delivers substantially enhanced performance with a formate Faradaic efficiency approaching 90% for 24 hours in a wide potential window. The formate Faradaic efficiency can be further increased by using isotope DO instead of HO. Density functional theory calculations suggest that the regenerative CeO/Bi interfacial sites can not only promote water activation to increase local H species for CO protonation appropriately, but also stabilize the key intermediate OCHO in formate pathway.
揭示催化剂在实际操作条件下的结构演变和工作机制对于设计用于CO电还原的高效电催化剂至关重要，但仍然极具挑战性。在此，借助多尺度水平的结构测量，发现在CO电还原条件下，制备的CeO/BiOCl预催化剂逐渐演变成具有富集Ce物种的CeO/Bi界面结构，该结构作为真正的催化活性相。与纯Bi对应物相比，衍生的CeO/Bi界面结构在宽电位窗口中在24小时内实现了大幅增强的性能，甲酸盐法拉第效率接近90%。通过使用同位素D₂O而非H₂O，甲酸盐法拉第效率可进一步提高。密度泛函理论计算表明，再生的CeO/Bi界面位点不仅可以促进水活化以适当增加用于CO质子化的局部H物种，还可以稳定甲酸盐途径中的关键中间体OCHO。
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