She Sixuan, Chen Changsheng, Fan Ke, Chen Gao, Zhu Yanping, Guan Daqin, Huang Yu-Cheng, Chen Hsiao-Chien, Lin Zezhou, Wong Hon Fai, Li Liuqing, Zhu Ye, Leung Chi Wah, Tsang Yuen Hong, Huang Haitao
Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
WA School of Mines: Minerals, Energy and Chemical Engineering (WASM-MECE), Curtin University, Perth, WA 6102, Australia.
J Am Chem Soc. 2025 Jul 16;147(28):24392-24402. doi: 10.1021/jacs.5c02857. Epub 2025 Jul 3.
Metal-support interaction (MSI) has profound impacts on the catalytic performance of heterogeneous catalysts. Rational modulation of MSI will give rise to unusually high activity and stability. Here, we demonstrate that the MSI strength can be effectively tuned by the tunnel size of MnO supports to help address the two fundamental challenges in Ru-based acidic oxygen evolution reaction (OER): the sluggish kinetics and the instability of Ru sites. Through crystallographic engineering from α-MnO to β-MnO polymorphs, we found that the reduced tunnel size of MnO increases planar oxygen (O) concentration and promotes the formation of strong Ru-O-Mn bonds, thereby enhancing the Ru/MnO interactions. However, an excessively small tunnel size in β-MnO leads to surface amorphization and elongated Ru-O-Mn bonds after Ru incorporation, thus reversely weakening the Ru/MnO interactions. Our work manifests distinct volcano-shaped dependencies for both MSI strength and OER activity as a function of the tunnel size of MnO supports. The optimized Ru-γ-MnO catalyst, featuring an intermediate tunnel size and the strongest MSI, achieves an exceptional mass activity (1743 A g at 1.5 V) while maintaining a high stability. Our results suggest that strong Ru-O-Mn interactions promote the formation of the OOH* intermediate through high Ru-O covalency and stabilize reactive Ru species against dissolution through double-exchange charge transfer from low-valence Mn sites. These findings offer valuable insights into the modulation of MSI via structural design of support for the optimization of other supported catalysts.
金属-载体相互作用（MSI）对多相催化剂的催化性能有着深远影响。对MSI进行合理调控将产生异常高的活性和稳定性。在此，我们证明MSI强度可通过MnO载体的隧道尺寸有效调节，以帮助解决基于Ru的酸性析氧反应（OER）中的两个基本挑战：缓慢的动力学和Ru位点的不稳定性。通过从α-MnO到β-MnO多晶型的晶体工程，我们发现MnO隧道尺寸的减小会增加平面氧（O）浓度，并促进强Ru-O-Mn键的形成，从而增强Ru/MnO相互作用。然而，β-MnO中过小的隧道尺寸会导致表面非晶化以及Ru掺入后Ru-O-Mn键伸长，从而反向削弱Ru/MnO相互作用。我们的工作表明，作为MnO载体隧道尺寸的函数，MSI强度和OER活性都呈现出明显的火山形依赖性。优化后的Ru-γ-MnO催化剂具有中等隧道尺寸和最强的MSI，在保持高稳定性的同时实现了卓越的质量活性（1.5 V下为1743 A g）。我们的结果表明，强Ru-O-Mn相互作用通过高Ru-O共价性促进OOH*中间体的形成，并通过低价Mn位点的双交换电荷转移稳定活性Ru物种以防止溶解。这些发现为通过载体结构设计调控MSI以优化其他负载型催化剂提供了有价值的见解。
