Confined catalysis under two-dimensional materials
Confined catalysis under two-dimensional materials
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二维材料下的限域催化
DOI：
10.1073/pnas.1701280114
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发表时间：
2017-06-06
影响因子：
11.1
通讯作者：
Bao, Xinhe
中科院分区：
文献类型：
--
作者：
Li, Haobo;Xiao, Jianping;Bao, Xinhe
意义 纳米反应器中的小空间可能对化学产生重大影响，因为纳米空间内分子和反应的化学性质可能由于纳米限制效应而发生显着变化。在二维材料下形成的二维（2D）纳米反应器可以提供明确的模型系统来探索受限催化。我们证明了在石墨烯覆盖层的限制下表面吸附减弱的总体趋势，说明了通过在表面顶部放置 2D 覆盖物来调节表面反应的可行方法。开发的概念“覆盖催化”可应用于两个相对的二维壁之间通过范德华力相互作用的反应，这有助于设计与二维材料覆盖层相互作用的高性能纳米催化剂。最近人们认识到非均相催化剂中形成的受限微环境与催化活性位点同等重要。了解受限催化的基本原理已成为多相催化的一个重要课题。催化剂表面和二维材料覆盖层之间明确定义的二维空间为实验和理论上探索受限催化提供了理想的微环境。利用密度泛函理论计算，我们发现单层石墨烯下原子和分子在Pt（111）表面上的吸附总是减弱，这归因于石墨烯覆盖层和Pt（111）表面之间的二维空间中的几何约束和限制场。在覆盖有石墨烯的 Pt(110) 和 Pt(100) 表面上也发现了类似的结果。通过用 2D 材料覆盖层涂覆催化剂表面所创建的微环境可用于调节表面反应性，这已通过优化各种 2D 材料覆盖的 Pt(111) 上的氧还原反应活性来说明。我们基于 2D 材料覆盖层和底层催化剂表面之间的弱范德华相互作用，展示了 2D 覆盖下受限催化的概念。
Significance Small spaces in nanoreactors may have big implications in chemistry, because the chemical nature of molecules and reactions within the nanospaces can be changed significantly due to the nanoconfinement effect. Two-dimensional (2D) nanoreactor formed under 2D materials can provide a well-defined model system to explore the confined catalysis. We demonstrate a general tendency for weakened surface adsorption under the confinement of graphene overlayer, illustrating the feasible modulation of surface reactions by placing a 2D cover on top of the surface. The developed concept “catalysis under cover” can be applied to reactions between two opposite 2D walls interacting with each other through van der Waals force, which helps to design high-performance nanocatalysts interfacing with 2D material overlayers. Confined microenvironments formed in heterogeneous catalysts have recently been recognized as equally important as catalytically active sites. Understanding the fundamentals of confined catalysis has become an important topic in heterogeneous catalysis. Well-defined 2D space between a catalyst surface and a 2D material overlayer provides an ideal microenvironment to explore the confined catalysis experimentally and theoretically. Using density functional theory calculations, we reveal that adsorption of atoms and molecules on a Pt(111) surface always has been weakened under monolayer graphene, which is attributed to the geometric constraint and confinement field in the 2D space between the graphene overlayer and the Pt(111) surface. A similar result has been found on Pt(110) and Pt(100) surfaces covered with graphene. The microenvironment created by coating a catalyst surface with 2D material overlayer can be used to modulate surface reactivity, which has been illustrated by optimizing oxygen reduction reaction activity on Pt(111) covered by various 2D materials. We demonstrate a concept of confined catalysis under 2D cover based on a weak van der Waals interaction between 2D material overlayers and underlying catalyst surfaces.