Wang Huimin, Chen Zhe-Ning, Wu Dongshuang, Cao Minna, Sun Fanfei, Zhang Hao, You Hanhui, Zhuang Wei, Cao Rong
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P. R. China.
University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
J Am Chem Soc. 2021 Mar 31;143(12):4639-4645. doi: 10.1021/jacs.0c12740. Epub 2021 Mar 3.
Developing efficient bifunctional electrocatalysts for overall water splitting in acidic conditions is the essential step for proton exchange membrane water electrolyzers (PEMWEs). We first report the synthesis of core-shell structure nanoparticles (NPs) with an Au core and an AuIr alloy shell (Au@AuIr). Au@AuIr displayed 4.6 (5.6) times higher intrinsic (mass) activity toward the oxygen evolution reaction (OER) than a commercial Ir catalyst. Furthermore, it showed hydrogen evolution reaction (HER) catalytic properties comparable to those of commercial Pt/C. Significantly, when Au@AuIr was used as both the anode and cathode catalyst, the overall water splitting cell achieved 10 mA/cm with a low cell voltage of 1.55 V and maintained this activity for more than 40 h, which greatly outperformed the commercial couples (Ir/C||Pt/C, 1.63 V, activity decreased within minutes) and is among the most efficient bifunctional catalysts reported. Theoretical calculations coupled with X-ray-based structural analyses suggest that partially oxidized surfaces originating from the electronic interaction between Au and Ir provide a balance for different intermediates binding and realize significantly enhanced OER performance.
开发用于酸性条件下全水解的高效双功能电催化剂是质子交换膜水电解槽（PEMWE）的关键步骤。我们首次报道了具有金核和金铱合金壳（Au@AuIr）的核壳结构纳米颗粒（NP）的合成。Au@AuIr对析氧反应（OER）的本征（质量）活性比市售铱催化剂高4.6（5.6）倍。此外，它表现出与市售Pt/C相当的析氢反应（HER）催化性能。值得注意的是，当Au@AuIr用作阳极和阴极催化剂时，全水解电池在1.55 V的低电池电压下实现了10 mA/cm²的电流密度，并保持该活性超过40小时，这大大优于市售催化剂对（Ir/C||Pt/C，1.63 V，活性在几分钟内下降），是报道的最有效的双功能催化剂之一。结合基于X射线的结构分析的理论计算表明，源自金和铱之间电子相互作用的部分氧化表面为不同中间体的结合提供了平衡，并实现了显著增强的OER性能。
