标题： 质量传输限制的反应速率和石墨烯下方范德华间隙中的分子扩散 显示英文标题

标题： Mass-transport-limited reaction rates and molecular diffusion in the van der Waals gap beneath graphene

摘要： 在二维2D材料与催化基底之间的范德华（vdW）间隙中限制分子，为开发具有更高反应速率的分子选择性催化剂提供了一条有前途的途径。 然而，确定这种受限反应的动力学限制仍然具有挑战性。 在此，我们采用多层石墨烯在铂上的倒置婚礼蛋糕结构，利用原位扫描电子显微镜研究各种分子（O2、H2和CO）在vdW间隙中的石墨烯蚀刻动力学。 在实验条件下（最高压力为1.4x10-3帕和温度为1000{\deg }C），蚀刻反应速率受到受限空间内质量传输的限制。 即使对于CO，尽管其由于vdW间隙显著提升而表现出异常增强的传输性能，这种限制仍然存在。 反应分子动力学模拟进一步揭示了CO在vdW空间中受限时的多种蚀刻路径。 一旦克服质量传输限制，vdW间隙就充当有效的纳米反应器，促进在无空间限制的原始表面上无法实现的反应路径。 显示英文摘要

摘要： The confinement of molecules within the van der Waals (vdW) gap between a two-dimensional 2D material and a catalytic substrate offers a promising route toward the development of molecule-selective catalysts with increased reaction rates. However, identifying the kinetic limitations of such confined reactions remains challenging. Here, we employ an inverted wedding-cake configuration of multilayer graphene on platinum to study the dynamics of graphene etching in the vdW gap by various molecules (O2, H2, and CO), using in situ scanning electron microscopy. Under the experimental conditions explored (up to p = 1.4x10-3 Pa and T = 1000 {\deg}C), the etching reaction rates are limited by mass transport within the confined space. This limitation persists even for CO, despite its anomalously enhanced transport resulting from a significant lifting of the vdW gap. Reactive molecular dynamics simulations further reveal multiple etching pathways for CO, enabled by confinement within the vdW space. Once mass-transport limitations are overcome, the vdW gap acts as an effective nanoreactor, facilitating reaction pathways that would be otherwise inaccessible on a pristine surface without spatial confinement.