Covalent organic frameworks (COFs) have emerged as an excellent support for heterogeneous catalysis due to their regular pore structure and high specific surface area. Herein, a series of porous TpPa-1 with different morphologies and structures were achieved by adjusting the ratio of water to acetic acid in the solvent-thermal process, and Pd@TpPa-1 catalysts were obtained with Pd solution impregnation. Notably, Pd@TpPa-1-100 prepared with 100 wt % water as the catalyst has superior catalytic properties in the phenol hydrogenation to cyclohexanone, and its turnover frequency (TOF) of 33.1 h^–1 is about 7 times higher than that of Pd@TpPa-1-0 synthesized with 100 wt % acetic acid as the catalyst. The two-dimensional (2D) nanosheet structures, highly dispersed Pd nanoparticles (NPs) with small particle size, and superhydrophilicity should be responsible for the superior catalytic performance of Pd@TpPa-1-100. Furthermore, Pd@TpPa-1-100 also has better catalytic performance in the hydrogenation of catechol, resorcinol, and hydroquinone than Pd@TpPa-1-0 and exhibits superior catalytic stability. This study provides a new approach for the structural regulation of metal-based COF catalysts.

中文翻译：

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负载在二维共价有机骨架上的Pd纳米颗粒具有增强的苯酚加氢催化性能

共价有机骨架（COF）由于其规则的孔结构和高的比表面积，已成为多相催化的极好支持。在此，通过溶剂热法调节水与乙酸的比例，制得了一系列不同形貌和结构的多孔TpPa-1，并通过Pd溶液浸渍得到了Pd @ TpPa-1催化剂。值得注意的是，以100 wt％的水为催化剂制备的Pd @ TpPa-1-100在苯酚加氢成环己酮方面具有优异的催化性能，其周转频率（TOF）为33.1 h ^–1比以100重量％乙酸为催化剂合成的Pd @ TpPa-1-0高约7倍。二维（2D）纳米片结构，高度分散的小粒径Pd纳米颗粒（NP）和超亲水性应归因于Pd @ TpPa-1-100的优异催化性能。此外，Pd @ TpPa-1-100在邻苯二酚，间苯二酚和对苯二酚的加氢中也具有比Pd @ TpPa-1-0更好的催化性能，并具有优异的催化稳定性。这项研究为金属基COF催化剂的结构调控提供了一种新方法。