A well-defined hexamethylenetetramine (abbreviated as HMTA) based two-dimensional (2D) MOFs metalloligand (termed Zn-HMTA), with free uncoordinated tertiary amine groups, has been synthesized via solution diffusion method for the first time. The crystal structure of 2D Zn-HMTA metalloligand was determined by the single crystal X-ray diffraction (SCXRD). The SCXRD and X-ray photoelectron spectroscopy (XPS) analyses have revealed that the 2D Zn-HMTA metalloligand is rich in- free tertiary amine groups, which are of strong coordination ability to transition metal ions (e.g. Ni²⁺, Co²⁺, Zn²⁺, Cu²⁺). As a result, a 2D bimetallic Co@Zn-HMTA MOFs was synthesized via coordination-assisted impregnation (CAI) strategy attributed to the unique feature of strong coordinated ability of free tertiary amine groups. Furthermore, a series of self-supported Co-ZnO-CN nanocatalysts were afforded upon the as-synthesized Co@Zn-HMTA MOFs served as a self-sacrificial template for pyrolysis at different temperatures. The optimized catalyst (termed as Co-ZnO@CN-CAI) demonstrated the excellent catalytic performance for hydrogenation-alkylation tandem reaction in comparison with the classic ZnO@CN composite (derived from Zn-HMTA MOFs) supported metallic Co catalyst (Co-ZnO@CN-IWI) prepared by incipient wetness impregnation method. Moreover, the kinetic study was also performed to confirm that the alkylation is the rate-determining step in the hydrogenation-alkylation tandem reaction. The origin of enhanced catalytic performance of Co-ZnO@CN-CAI and the role of Co@Zn-HMTA MOFs precursor have been explored by way of various characterizations, e.g. HADDF-STEM-EDS, SEM-EDS, ¹³C MAS NMR, XRD, Raman and XPS, etc. It is anticipated that the prepared low-cost and easily prepared 2D Zn-HMTA metalloligand will become a general template for synthesis of highly self-supported catalysts with coordination-assisted impregnation strategy (CAI) for various catalytic reactions.

首次通过溶液扩散法合成了一种明确定义的六亚甲基四胺（缩写为HMTA）基于二维（2D）MOFs 金属配体（称为 Zn- HMTA），具有游离的未配位叔胺基团。二维Zn- HMTA金属配体的晶体结构由单晶 X 射线衍射 (SCXRD) 确定。SCXRD和X射线光电子能谱（XPS）分析表明，二维Zn- HMTA金属配体富含游离的叔胺基团，对过渡金属离子（如Ni ²⁺、Co ²⁺、 Zn ²⁺、Cu ²⁺ )。结果，二维双金属 Co@Zn-HMTA MOFs 是通过配位辅助浸渍 (CAI) 策略合成的，这归因于游离叔胺基团具有强配位能力的独特特征。此外，在合成的 Co@Zn- HMTA MOFs 上提供了一系列自支撑的 Co-ZnO-CN 纳米催化剂，作为在不同温度下热解的自牺牲模板。优化后的催化剂（称为 Co-ZnO@CN-CAI）与经典的 ZnO@CN 复合材料（源自 Zn- HMTAMOFs) 负载的金属 Co 催化剂 (Co-ZnO@CN-IWI) 通过初湿浸渍法制备。此外，还进行了动力学研究以确认烷基化是氢化-烷基化串联反应中的限速步骤。Co-ZnO@CN-CAI 催化性能增强的原因和 Co@ Zn- HMTA MOFs 前驱体的作用已经通过各种表征进行了探索，例如 HADDF-STEM-EDS、SEM-EDS、¹³ C MAS NMR、 XRD、Raman 和 XPS 等。预计制备的低成本且易于制备的二维 Zn- HMTA金属配体将成为合成具有配位辅助浸渍策略（CAI）的高自载催化剂的通用模板，用于各种催化反应。