Li Junjie, Banis Mohammad Norouzi, Ren Zhouhong, Adair Keegan R, Doyle-Davis Kieran, Meira Debora Motta, Finfrock Y Zou, Zhang Lei, Kong Fanpeng, Sham Tsun-Kong, Li Ruying, Luo Jun, Sun Xueliang
Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ontario, N6A 5B9, Canada.
Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin, 300384, China.
Small. 2021 Mar;17(11):e2007245. doi: 10.1002/smll.202007245. Epub 2021 Feb 19.
Single-atom catalysts (SACs) have attracted significant attention due to their superior catalytic activity and selectivity. However, the nature of active sites of SACs under realistic reaction conditions is ambiguous. In this work, high loading Pt single atoms on graphitic carbon nitride (g-C N )-derived N-doped carbon nanosheets (Pt /NCNS) is achieved through atomic layer deposition. Operando X-ray absorption spectroscopy (XAS) is performed on Pt single atoms and nanoparticles (NPs) in both the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). The operando results indicate that the total unoccupied density of states of Pt 5d orbitals of Pt atoms is higher than that of Pt NPs under HER condition, and that a stable Pt oxide is formed during ORR on Pt /NCNS, which may suppress the adsorption and activation of O . This work unveils the nature of Pt single atoms under realistic HER and ORR conditions, providing a deeper understanding for designing advanced SACs.
单原子催化剂（SACs）因其卓越的催化活性和选择性而备受关注。然而，在实际反应条件下单原子催化剂活性位点的本质尚不明确。在这项工作中，通过原子层沉积法在石墨相氮化碳（g-C₃N₄）衍生的氮掺杂碳纳米片（Pt/NCNS）上实现了高负载量的铂单原子。在析氢反应（HER）和氧还原反应（ORR）中，对铂单原子和纳米颗粒（NPs）进行了原位X射线吸收光谱（XAS）研究。原位研究结果表明，在HER条件下，铂原子的铂5d轨道的总未占据态密度高于铂纳米颗粒，并且在Pt/NCNS上的ORR过程中形成了稳定的铂氧化物，这可能会抑制O₂的吸附和活化。这项工作揭示了在实际HER和ORR条件下铂单原子的本质，为设计先进的单原子催化剂提供了更深入的理解。
