title: Metal-organic frameworks as selectivity regulators for hydrogenation reactions.
abstract: Owing to the limited availability of natural sources, the widespread demand of the flavouring, perfume and pharmaceutical industries for unsaturated alcohols is met by producing them from α,β-unsaturated aldehydes, through the selective hydrogenation of the carbon-oxygen group (in preference to the carbon-carbon group). However, developing effective catalysts for this transformation is challenging, because hydrogenation of the carbon-carbon group is thermodynamically favoured. This difficulty is particularly relevant for one major category of heterogeneous catalyst: metal nanoparticles supported on metal oxides. These systems are generally incapable of significantly enhancing the selectivity towards thermodynamically unfavoured reactions, because only the edges of nanoparticles that are in direct contact with the metal-oxide support possess selective catalytic properties; most of the exposed nanoparticle surfaces do not. This has inspired the use of metal-organic frameworks (MOFs) to encapsulate metal nanoparticles within their layers or inside their channels, to influence the activity of the entire nanoparticle surface while maintaining efficient reactant and product transport owing to the porous nature of the material. Here we show that MOFs can also serve as effective selectivity regulators for the hydrogenation of α,β-unsaturated aldehydes. Sandwiching platinum nanoparticles between an inner core and an outer shell composed of an MOF with metal nodes of Fe3+, Cr3+or both (known as MIL-101; refs 19, 20, 21) results in stable catalysts that convert a range of α,β-unsaturated aldehydes with high efficiency and with significantly enhanced selectivity towards unsaturated alcohols. Calculations reveal that preferential interaction of MOF metal sites with the carbon-oxygen rather than the carbon-carbon group renders hydrogenation of the former by the embedded platinum nanoparticles a thermodynamically favoured reaction. We anticipate that our basic design strategy will allow the development of other selective heterogeneous catalysts for important yet challenging transformations.
authors.affiliation: Chinese Academy of Sciences (CAS) Key Laboratory of Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
authors.forename: Meiting
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Chinese Academy of Sciences (CAS) Key Laboratory of Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.|School of Science, Tianjin University, Tianjin 300072, China.
authors.forename: Kuo
authors.initials: K
authors.lastname: Yuan
authors.affiliation: Centre for Clean Environment and Energy, Gold Coast Campus, Griffith University, Queensland 4222, Australia.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Chinese Academy of Sciences (CAS) Key Laboratory of Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Li
authors.affiliation: Chinese Academy of Sciences (CAS) Key Laboratory of Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Gu
authors.affiliation: School of Science, Tianjin University, Tianjin 300072, China.|Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Wenping
authors.initials: W
authors.lastname: Hu
authors.affiliation: Centre for Clean Environment and Energy, Gold Coast Campus, Griffith University, Queensland 4222, Australia.
authors.forename: Huijun
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Chinese Academy of Sciences (CAS) Key Laboratory of Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Tang
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D000447:Aldehydes / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry; D006865:Hydrogenation; D053768:Metal Nanoparticles / Q000737:chemistry*; D000073396:Metal-Organic Frameworks; D010087:Oxides / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*
chemical_list: D000438:Alcohols; D000447:Aldehydes; D056831:Coordination Complexes; C000589635:MIL-101; D000073396:Metal-Organic Frameworks; D010087:Oxides; D010984:Platinum; D002244:Carbon