Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon 34141, South Korea.
Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States.
J Am Chem Soc. 2021 Apr 14;143(14):5355-5363. doi: 10.1021/jacs.0c11261. Epub 2021 Mar 17.
The extraordinary mass activity of jagged Pt nanowires can substantially improve the economics of the hydrogen evolution reaction (HER). However, it is a great challenge to fully unveil the HER kinetics driven by the jagged Pt nanowires with their multiscale morphology. Herein we present an end-to-end framework that combines experiment, machine learning, and multiscale advances of the past decade to elucidate the HER kinetics catalyzed by jagged Pt nanowires under alkaline conditions. The bifunctional catalysis conventionally refers to the synergistic increase in activity by the combination of two different catalysts. We report that monometals, such as jagged Pt nanowires, can exhibit bifunctional characteristics owing to its complex surface morphology, where one site prefers electrochemical proton adsorption and another is responsible for activation, resulting in a 4-fold increase in the activity. We find that the conventional design guideline that the sites with a 0 eV Gibbs free energy of adsorption are optimal for HER does not hold under alkaline conditions, and rather, an energy between -0.2 and 0.0 eV is shown to be optimal. At the reaction temperatures, the high activity arises from low-coordination-number (≤7) Pt atoms exposed by the jagged surface. Our current demonstration raises an emerging prospect to understand highly complex kinetic phenomena on the nanoscale in full by implementing end-to-end multiscale strategies.
锯齿状 Pt 纳米线的非凡质量活性可以大大提高析氢反应（HER）的经济性。然而，充分揭示锯齿状 Pt 纳米线驱动的 HER 动力学仍然是一个巨大的挑战，因为它们具有多尺度形貌。在此，我们提出了一个端到端的框架，该框架结合了实验、机器学习和过去十年的多尺度进展，以阐明碱性条件下锯齿状 Pt 纳米线催化的 HER 动力学。双功能催化通常是指通过两种不同催化剂的组合协同增加活性。我们报告说，单金属（例如锯齿状 Pt 纳米线）由于其复杂的表面形态可以表现出双功能特性，其中一个位点优先进行电化学质子吸附，另一个位点负责活化，从而使活性提高了 4 倍。我们发现，传统的设计准则认为吸附能为 0 eV 的 Gibbs 自由能的位点对 HER 是最优的，在碱性条件下并不成立，而在 -0.2 到 0.0 eV 之间的能量则显示出最优性。在反应温度下，锯齿状表面暴露的低配位数（≤7）Pt 原子导致了高活性。我们目前的研究结果提出了一个新的前景，即通过实施端到端的多尺度策略，全面理解纳米尺度上的高度复杂动力学现象。
