中国科学技术大学江海龙团队报道了金属-有机框架实现调制微环境中表面清洁Au25纳米团簇催化增强。相关研究成果于2022年11月21日发表在国际顶尖学术期刊《美国化学会杂志》。

具有原子精确结构的金属纳米簇（NCs）引发了人们对催化的兴趣。不幸的是，它们的高聚集倾向和表面配体的空间阻力构成了重大挑战。

该文中，Au25 NCs被封装在同网状金属-有机框架（MOFs）中，即UiO-66-X（X=H、NH₂、OH和NO₂），然后去除Au25 NCs上的表面配体。所得到的表面清洁的Au25NCs，受到MOF空间限制的保护，在糠醛的氧化酯化中表现出比原始Au25NCs高得多的活性和稳定性。值得注意的是，实验和理论结果共同表明，UiO-66-X上的不同官能团调节Au25电子态，从而产生不同的Au25@UiO-66-X底物吸附能。因此，高电子密度和合适的基质吸附能力主导了活性趋势：Au25@UiO-66-NH2 > Au25@UiO-66-OH > Au25@UiO-66 > Au25@UiO-66-NO2.

该项工作为在孔壁工程MOFs中稳定表面清洁金属NCs以增强催化作用开发了一种新策略。

附：英文原文

Title: Surface-Clean Au25 Nanoclusters in Modulated Microenvironment Enabled by Metal–Organic Frameworks for Enhanced Catalysis

Author: He Wang, Xiyuan Liu, Weijie Yang, Guangyang Mao, Zheng Meng, Zhikun Wu, Hai-Long Jiang

Issue&Volume: November 21, 2022

Abstract: Metal nanoclusters (NCs) with atomically precise structures have sparked interest in catalysis. Unfortunately, their high aggregation tendency and the spatial resistance of surface ligands pose significant challenges. Herein, Au25 NCs are encapsulated into isoreticular metal–organic frameworks (MOFs), namely UiO-66-X (X = H, NH2, OH, and NO2), followed by the removal of surface ligands on Au25 NCs. The resulting surface-clean Au25 NCs, protected by the MOF spatial confinement, exhibit much superior activity and stability with respect to pristine Au25 NCs in the oxidative esterification of furfural. Remarkably, experimental and theoretical results jointly demonstrate that diverse functional groups on UiO-66-X modulate the Au25 electronic state, giving rise to the discriminated substrate adsorption energy of Au25@UiO-66-X. As a result, the high electron density and suitable substrate adsorption ability dominate the activity trend: Au25@UiO-66-NH2 > Au25@UiO-66-OH > Au25@UiO-66 > Au25@UiO-66-NO2. This work develops a new strategy for the stabilization of surface-clean metal NCs in pore wall-engineered MOFs for enhanced catalysis.

DOI: 10.1021/jacs.2c09136

Source: https://pubs.acs.org/doi/10.1021/jacs.2c09136