Hou Chun-Chao, Zou Lianli, Sun Liming, Zhang Kexin, Liu Zheng, Li Yinwei, Li Caixia, Zou Ruqiang, Yu Jihong, Xu Qiang
AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory (ChEM-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Sakyo-ku, Kyoto, 606-8501, Japan.
Graduate School of Engineering, Kobe University, Nada Ku, Kobe, Hyogo, 657-8501, Japan.
Angew Chem Int Ed Engl. 2020 May 4;59(19):7384-7389. doi: 10.1002/anie.202002665. Epub 2020 Mar 25.
Single-atom catalysts have drawn great attention, especially in electrocatalysis. However, most of previous works focus on the enhanced catalytic properties via improving metal loading. Engineering morphologies of catalysts to facilitate mass transport through catalyst layers, thus increasing the utilization of each active site, is regarded as an appealing way for enhanced performance. Herein, we design an overhang-eave structure decorated with isolated single-atom iron sites via a silica-mediated MOF-templated approach for oxygen reduction reaction (ORR) catalysis. This catalyst demonstrates superior ORR performance in both alkaline and acidic electrolytes, comparable to the state-of-the-art Pt/C catalyst and superior to most precious-metal-free catalysts reported to date. This activity originates from its edge-rich structure, having more three-phase boundaries with enhanced mass transport of reactants to accessible single-atom iron sites (increasing the utilization of active sites), which verifies the practicability of such a synthetic approach.
单原子催化剂已引起了极大关注，尤其是在电催化领域。然而，以前的大多数工作都集中在通过提高金属负载量来增强催化性能。设计催化剂的形态以促进物质通过催化剂层的传输，从而提高每个活性位点的利用率，被认为是提高性能的一种有吸引力的方法。在此，我们通过二氧化硅介导的金属有机框架模板法设计了一种带有孤立单原子铁位点的屋檐悬垂结构，用于氧还原反应（ORR）催化。这种催化剂在碱性和酸性电解质中均表现出优异的ORR性能，与目前最先进的Pt/C催化剂相当，且优于迄今为止报道的大多数无贵金属催化剂。这种活性源于其富含边缘的结构，具有更多的三相边界，增强了反应物向可及的单原子铁位点的传质（提高了活性位点的利用率），这验证了这种合成方法的实用性。
