Arulmozhi Nakkiran, Hanselman Selwyn, Tudor Viorica, Chen Xiaoting, van Velden David, Schneider Grégory F, Calle-Vallejo Federico, Koper Marc T M
Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands.
Department of Materials Science and Chemical Physics & Institute of Theoretical and Computational Chemistry (IQTCUB), University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
JACS Au. 2023 Jan 18;3(2):526-535. doi: 10.1021/jacsau.2c00648. eCollection 2023 Feb 27.
The Angstrom-scale space between graphene and its substrate provides an attractive playground for scientific exploration and can lead to breakthrough applications. Here, we report the energetics and kinetics of hydrogen electrosorption on a graphene-covered Pt(111) electrode using electrochemical experiments, in situ spectroscopy, and density functional theory calculations. The graphene overlayer influences the hydrogen adsorption on Pt(111) by shielding the ions from the interface and weakening the Pt-H bond energy. Analysis of the proton permeation resistance with controlled graphene defect density proves that the domain boundary defects and point defects are the pathways for proton permeation in the graphene layer, in agreement with density functional theory (DFT) calculations of the lowest energy proton permeation pathways. Although graphene blocks the interaction of anions with the Pt(111) surfaces, anions do adsorb near the defects: the rate constant for hydrogen permeation is sensitively dependent on anion identity and concentration.
石墨烯与其基底之间埃尺度的空间为科学探索提供了一个极具吸引力的领域，并可能带来突破性的应用。在此，我们通过电化学实验、原位光谱和密度泛函理论计算，报告了氢在石墨烯覆盖的Pt(111)电极上的电吸附能学和动力学。石墨烯覆盖层通过屏蔽界面处的离子并削弱Pt-H键能，影响氢在Pt(111)上的吸附。对具有可控石墨烯缺陷密度的质子渗透电阻的分析表明，畴界缺陷和点缺陷是质子在石墨烯层中渗透的途径，这与最低能量质子渗透途径的密度泛函理论(DFT)计算结果一致。尽管石墨烯阻碍了阴离子与Pt(111)表面的相互作用，但阴离子确实吸附在缺陷附近：氢渗透的速率常数敏感地依赖于阴离子的种类和浓度。
