Zhang Weijie, Qin Ruixuan, Fu Gang, Zheng Nanfeng
State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National & Local Joint Engineering Research Center for Preparation Technology of Nanomaterials, and National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361102, China.
J Am Chem Soc. 2023 May 10;145(18):10178-10186. doi: 10.1021/jacs.3c00953. Epub 2023 Apr 28.
Tuning the metal-ligand interfaces of heterogeneous catalysts has emerged as an effective strategy to optimize their catalytic performance. However, improving the selectivity via organic modification remains a challenge so far. In this work, we demonstrate a simple ligand modification by preparing cysteamine-coated ultrathin palladium nanosheets. The as-prepared catalyst exhibits excellent selectivity with durability during catalytic hydrogenation of terminal alkynes, superior to most previously reported ligand-protected palladium catalysts. Further study reveals that a zwitterionic transformation occurs on the palladium interface under the H conditions, generating a rigid hydrogen bond network. Such an unexpected effect beyond the traditional steric effect derived from van der Waals interactions makes the catalytic surface favor the hydrogenation of alkynes over alkenes without significantly sacrificing the catalytic activity. These results not only provide a unique steric effect concept for surface coordination chemistry but also provide a practical application to improve the selectivity and activity comprehensively.
调节多相催化剂的金属-配体界面已成为优化其催化性能的有效策略。然而，迄今为止，通过有机修饰提高选择性仍然是一个挑战。在这项工作中，我们通过制备半胱胺包覆的超薄钯纳米片展示了一种简单的配体修饰方法。所制备的催化剂在末端炔烃的催化氢化过程中表现出优异的选择性和耐久性，优于大多数先前报道的配体保护钯催化剂。进一步的研究表明，在氢气条件下钯界面上发生了两性离子转变，形成了刚性氢键网络。这种超出传统范德华相互作用产生的空间效应的意外效果，使得催化表面在不显著牺牲催化活性的情况下，更有利于炔烃而非烯烃的氢化。这些结果不仅为表面配位化学提供了独特的空间效应概念，也为全面提高选择性和活性提供了实际应用。
