Tong Miaomiao, Sun Fanfei, Xie Ying, Wang Ying, Yang Yuqi, Tian Chungui, Wang Lei, Fu Honggang
Key Laboratory of Superlight Materials and Surface Technology of the Ministry of Education of the People's Republic of China, Harbin Engineering University, Harbin, 150080, China.
Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China.
Angew Chem Int Ed Engl. 2021 Jun 14;60(25):14005-14012. doi: 10.1002/anie.202102053. Epub 2021 May 13.
Dual-metal single-atom catalysts exhibit superior performance for oxygen reduction reaction (ORR), however, the synergistic catalytic mechanism is not deeply understood. Herein, we report a dual-metal single-atom catalyst consisted of Cu-N and Zn-N on the N-doped carbon support (Cu/Zn-NC). It exhibits high-efficiency ORR activity with an E of 0.98 V and an E of 0.83 V, excellent stability (no degradation after 10 000 cycles), surpassing state-of-the-art Pt/C and great mass of Pt-free single atom catalysts. Operando XANES demonstrates that the Cu-N as active center experiences the change from atomic dispersion to cluster with the cooperation of Zn-N during ORR process, and then turns to single atom state again after reaction. DFT calculation further indicates that the adjustment effect of Zn on the d-orbital electron distribution of Cu could benefit to the stretch and cleavage of O-O on Cu active center, speeding up the process of rate determining step of OOH*.
双金属单原子催化剂在氧还原反应（ORR）中表现出优异的性能，然而，其协同催化机制尚未得到深入理解。在此，我们报道了一种由氮掺杂碳载体上的Cu-N和Zn-N组成的双金属单原子催化剂（Cu/Zn-NC）。它具有高效的ORR活性，E为0.98 V，E为0.83 V，具有出色的稳定性（10000次循环后无降解），超过了目前最先进的Pt/C以及大量无Pt单原子催化剂。原位X射线吸收近边结构（XANES）表明，作为活性中心的Cu-N在ORR过程中与Zn-N协同作用经历了从原子分散到簇状的变化，反应后又变回单原子状态。密度泛函理论（DFT）计算进一步表明，Zn对Cu的d轨道电子分布的调节作用有利于Cu活性中心上O-O的拉伸和断裂，加速了OOH*速率决定步骤的过程。
