Lee Yonghyuk, Scheurer Christoph, Reuter Karsten
Department of Chemistry, Chair of Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstraße, 85747, Garching, Germany.
Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany.
ChemSusChem. 2022 May 20;15(10):e202200015. doi: 10.1002/cssc.202200015. Epub 2022 Apr 13.
Due to their high activity and favorable stability in acidic electrolytes, Ir and Ru oxides are primary catalysts for the oxygen evolution reaction (OER) in proton-exchange membrane (PEM) electrolyzers. For a future large-scale application, core-shell nanoparticles are an appealing route to minimize the demand for these precious oxides. Here, we employ first-principles density-functional theory (DFT) and ab initio thermodynamics to assess the feasibility of encapsulating a cheap rutile-structured TiO core with coherent, monolayer-thin IrO or RuO films. Resulting from a strong directional dependence of adhesion and strain, a wetting tendency is only obtained for some low-index facets under typical gas-phase synthesis conditions. Thermodynamic stability in particular of lattice-matched RuO films is instead indicated for more oxidizing conditions. Intriguingly, the calculations also predict an enhanced activity and stability of such epitaxial RuO /TiO core-shell particles under OER operation.
由于铱（Ir）和钌（Ru）的氧化物在酸性电解质中具有高活性和良好的稳定性，它们是质子交换膜（PEM）电解槽中析氧反应（OER）的主要催化剂。对于未来的大规模应用，核壳纳米颗粒是减少这些珍贵氧化物需求的一条有吸引力的途径。在此，我们采用第一性原理密度泛函理论（DFT）和从头算热力学来评估用相干的单层IrO或RuO薄膜包裹廉价的金红石结构TiO核的可行性。由于附着力和应变具有很强的方向依赖性，在典型的气相合成条件下，仅在一些低指数晶面上出现了润湿趋势。相反，在氧化性更强的条件下，特别是晶格匹配的RuO薄膜具有热力学稳定性。有趣的是，计算还预测了这种外延RuO/TiO核壳颗粒在OER操作下具有增强的活性和稳定性。
