Luo Fang, Hu Hao, Zhao Xiao, Yang Zehui, Zhang Quan, Xu Jingxiang, Kaneko Takuma, Yoshida Yusuke, Zhu Chengzhou, Cai Weiwei
Sustainable Energy Laboratory, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
Innovation Research Center for Fuel Cells, The University of Electro-Communications, Chofugaoka, Chofu, Tokyo 182-8585, Japan.
Nano Lett. 2020 Mar 11;20(3):2120-2128. doi: 10.1021/acs.nanolett.0c00127. Epub 2020 Feb 7.
Single-atom electrocatalysts (SAEs) can realize the target of low-cost by maximum atomic efficiency. However, they usually suffer performance decay due to high energy states, especially in a harsh acidic water splitting environment. Here, we conceive and realize a double protecting strategy that ensures robust acidic water splitting on Ir SAEs by dispersing Ir atoms in/onto Fe nanoparticles and embedding IrFe nanoparticles into nitrogen-doped carbon nanotubes (Ir-SA@Fe@NCNT). When Ir-SA@Fe@NCNT acts as a bifunctional electrocatalyst at ultralow Ir loading of 1.14 μg cm, the required overpotentials to deliver 10 mA cm are 250 and 26 mV for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in 0.5 M HSO electrolyte corresponding to 1370- and 61-fold better mass activities than benchmark IrO and Pt/C at an overpotential of 270 mV, respectively, resulting in only 1.51 V to drive overall water splitting. Moreover, remarkable stability is also observed compared to Pt/C-IrO.
单原子电催化剂（SAEs）可以通过最大化原子效率实现低成本目标。然而，它们通常会由于高能态而出现性能衰减，尤其是在苛刻的酸性水分解环境中。在此，我们构思并实现了一种双重保护策略，通过将铱原子分散在铁纳米颗粒内部/表面以及将铱铁纳米颗粒嵌入氮掺杂碳纳米管（Ir-SA@Fe@NCNT）中来确保铱单原子电催化剂在酸性条件下实现稳健的析氢反应。当Ir-SA@Fe@NCNT在超低铱负载量为1.14 μg cm时作为双功能电催化剂，在0.5 M HSO电解液中，析氧反应（OER）和析氢反应（HER）达到10 mA cm所需的过电位分别为250和26 mV，在270 mV过电位下，其质量活性分别比基准IrO和Pt/C高1370倍和61倍，仅需1.51 V就能驱动全解水。此外，与Pt/C-IrO相比，还观察到了显著的稳定性。
