Copper-Based Intermetallic Electride Catalyst for Chemoselective Hydrogenation Reactions.
Copper-Based Intermetallic Electride Catalyst for Chemoselective Hydrogenation Reactions.
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DOI：
10.1021/jacs.7b08252
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发表时间：
2017-11
影响因子：
15
通讯作者：
Tiannan Ye;Yangfan Lu;Jiang Li;T. Nakao;Hongsheng Yang;T. Tada;M. Kitano;H. Hosono
中科院分区：
文献类型：
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作者：
Tiannan Ye;Yangfan Lu;Jiang Li;T. Nakao;Hongsheng Yang;T. Tada;M. Kitano;H. Hosono
过渡金属间化合物是一种将活性中心引入到晶格骨架中的化合物，它的发展在调节活性中心的局域结构和电子性质、提高催化活性和稳定性方面具有巨大的潜力。本文报道了一种新的铜基金属间化合物催化剂LaCu0.67Si1.33，其中被低功函数的阴离子电子活化的铜中心原子分散在晶格骨架中，对硝基芳烃的选择性加氢反应的转化率(TOF高达5084h-1)比已有的金属负载催化剂高40倍以上。利用同位素效应进行的动力学分析表明，H-H键的断裂是决定反应速率的步骤。令人惊讶的是，LaCu0.67Si1.33的高载流子密度和低功函数特性使氢分子能够以极低的活化能(Ea=14.8kJ·mol-1)被激活。此外，LaCu0.67Si1.33表面的高氧亲和力实现了硝基对硝基芳烃的优先吸附，从而导致了高的化学选择性。本发明的高效催化剂可进一步引发醛、酮等其他含氧官能团的高活性加氢反应。这些结果表明，特定晶位上的过渡金属起到了催化活性中心的作用，并且在活性和稳定性上超过了传统的金属负载催化剂。
The development of transition metal intermetallic compounds, in which active sites are incorporated in lattice frameworks, has great potential for modulating the local structure and the electronic properties of active sites, and enhancing the catalytic activity and stability. Here we report that a new copper-based intermetallic electride catalyst, LaCu0.67Si1.33, in which Cu sites activated by anionic electrons with low work function are atomically dispersed in the lattice framework and affords selective hydrogenation of nitroarenes with above 40-times higher turnover frequencies (TOFs up to 5084 h-1) than well-studied metal-loaded catalysts. Kinetic analysis utilizing isotope effect reveals that the cleavage of the H-H bond is the rate-determining step. Surprisingly, the high carrier density and low work function (LWF) properties of LaCu0.67Si1.33 enable the activation of hydrogen molecules with extreme low activation energy (Ea = 14.8 kJ·mol-1). Furthermore, preferential adsorption of nitroarenes via a nitro group is achieved by high oxygen affinity of LaCu0.67Si1.33 surface, resulting in high chemoselectivity. The present efficient catalyst can further trigger the hydrogenation of other oxygen-containing functional groups such as aldehydes and ketones with high activities. These findings demonstrate that the transition metals incorporated in the specific lattice site function as catalytically active centers and surpass the conventional metal-loaded catalysts in activity and stability.