Li Xiumin, Yang Pengfei, Zhang Xinyi, Liu Yanan, Miao Chenglin, Feng Junting, Li Dianqing
State Key Laboratory of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Beijing Engineering Center for Hierarchical Catalysts, Beijing University of Chemical Technology, Beijing 100029, China.
ACS Appl Mater Interfaces. 2021 May 19;13(19):22292-22303. doi: 10.1021/acsami.1c01225. Epub 2021 May 11.
In this work, we synthesized a series of Cu/ZrO catalysts with tunable V-Cu (oxygen vacancy adjacent to Cu metal) and V-Cu (zirconium vacancy adjacent to electron-deficient Cu species) dual-interface sites and investigated the role of the dual-interface sites in the 5-hydroxymethylfurfural (5-HMF) hydrogenolysis reaction with isopropanol as the hydrogen source. By combining a series of infrared characterization and catalytic performance analysis, it is identified that V-Cu interface sites were responsible for activating isopropanol dehydrogenation and C═O dissociation of 5-HMF, while the V-Cu interface sites were responsible for the dehydroxylation of an intermediate product 5-methyl-2-furfuryl alcohol (5-MFA). Specifically, C-OH was first deprotonated on the V at the V-Cu interface site to reduce the activation energy of 5-MFA dehydroxylation and then adjacent Cu promoted the dissociation of the C-O bond by enhancing the adsorption energy while elongating the C-O bond, as confirmed by the density functional theory calculations. Because the dual-interface sites provided separate sites for activating intermediate products and reactants, the coupling reaction caused by competitive adsorption is thus well avoided. Therefore, the optimized Cu/ZrO catalyst with the most V-Cu and moderate V-Cu sites exhibited 98.4% of 2,5-dimethylfuran yield under the conditions of 180 °C and self-vapor pressure.
在本工作中，我们合成了一系列具有可调V-Cu（与Cu金属相邻的氧空位）和V-Cu（与缺电子Cu物种相邻的锆空位）双界面位点的Cu/ZrO催化剂，并研究了双界面位点在以异丙醇为氢源的5-羟甲基糠醛（5-HMF）氢解反应中的作用。通过结合一系列红外表征和催化性能分析，确定V-Cu界面位点负责激活异丙醇脱氢和5-HMF的C═O解离，而V-Cu界面位点负责中间产物5-甲基-2-糠醇（5-MFA）的脱羟基化。具体而言，C-OH首先在V-Cu界面位点的V上发生去质子化，以降低5-MFA脱羟基化的活化能，然后相邻的Cu通过增强吸附能并延长C-O键来促进C-O键的解离，这一点得到了密度泛函理论计算的证实。由于双界面位点为激活中间产物和反应物提供了独立的位点，因此很好地避免了由竞争吸附引起的偶联反应。因此，具有最多V-Cu和适度V-Cu位点的优化Cu/ZrO催化剂在180℃和自蒸气压条件下表现出98.4%的2,5-二甲基呋喃产率。
