The dynamic evolution and structure-performance relationships of single-atom catalysts (SACs) under operating conditions are one of the most concerned hotspots at present. Here, we employed Anderson-type polyoxometalates as a precursor to prepare the SAC Rh-MoS, which shows excellent hydrogen evolution reaction (HER) performance with a mass activity of 4.26 A mg at 100 mV. Such a result is much better than that of 20% Pt/C. Extensive experimental characterization combined with density functional theory (DFT) calculations suggest that the active site undergoes a dynamic evolution from Rh-S to Rh-S/O, while at the same time, the support is transformed from 1T MoS to 1T-2H MoS. It is this dynamic evolution of the catalyst structure that causes a series of changes in the activity, and eventually, a balance between catalytic activity and stability is achieved. This work offers a good research demonstration of the dynamic evolution of SACs under operating conditions and provides a new perspective on the design of SACs.

中文翻译：

---

单原子Rh位点的动态演化和MoS2对析氢的支持


单原子催化剂（SAC）在操作条件下的动态演化和结构-性能关系是目前最受关注的热点之一。在这里，我们采用 Anderson 型多金属氧酸盐作为前驱体来制备 SAC Rh-MoS，它表现出优异的析氢反应 (HER) 性能，在 100 mV 下的质量活性为 4.26 A mg。这样的结果比20％Pt/C的结果要好得多。大量的实验表征结合密度泛函理论（DFT）计算表明，活性位点经历了从Rh-S到Rh-S/O的动态演化，同时载体从1T MoS转变为1T-2H MoS 。正是催化剂结构的这种动态演化引起了活性的一系列变化，最终实现催化活性和稳定性之间的平衡。这项工作为 SAC 在运行条件下的动态演化提供了良好的研究论证，并为 SAC 的设计提供了新的视角。