| Institution: | 1. Department State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, 130012 Changchun, China;2. School of Materials Science and Engineering, State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, 300387 Tianjin, China;3. Electron Microscopy Center, Jilin University, 130012 Changchun, China;4. College of Chemistry and Materials Science, Hebei University, 071002 Baoding, China;5. Department State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, 130012 Changchun, China
Center for High-resolution Electron Microscopy (C?EM), School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China;6. Bruker (Beijing) Scientific Technology Co., Ltd., 100000 Beijing, China;7. Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, 46022 Valencia, España |
| Abstract: | The selective hydrogenation of alkynes to alkenes is a crucial step in the synthesis of fine chemicals. However, the widely utilized palladium (Pd)-based catalysts often suffer from poor selectivity. In this work, we demonstrate a carbonization-reduction method to create palladium carbide subnanometric species within pure silicate MFI zeolite. The carbon species can modify the electronic and steric characteristics of Pd species by forming the predominant Pd?C4 structure and, meanwhile, facilitate the desorption of alkenes by forming the Si?O?C structure with zeolite framework, as validated by the state-of-the-art characterizations and theoretical calculations. The developed catalyst shows superior performance in the selective hydrogenation of alkynes over mild conditions (298 K, 2 bar H2), with 99 % selectivity to styrene at a complete conversion of phenylacetylene. In contrast, the zeolite-encapsulated carbon-free Pd catalyst and the commercial Lindlar catalyst show only 15 % and 14 % selectivity to styrene, respectively, under identical reaction conditions. The zeolite-confined Pd-carbide subnanoclusters promise their superior properties in semihydrogenation of alkynes. |
