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Tandem nanocatalyst design: putting two step-reaction sites into one location towards enhanced hydrogen transfer reactions

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Science China Materials 2019年第9期62卷 1297-1305页

作者： Yang You Hao Huang Keke Mao Song Xia Di Wu Canyu Hu Chao Gao Panyiming Liu Ran Long Xiaojun Wu Yujie Xiong Hefei National Laboratory for Physical Sciences at the Microscale Collaborative Innovation Center of Chemistry for Energy Materials (iChEM) School of Chemistry and Materials Science and National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230026 China School of Energy and Environment Science Anhui University of Technology Maanshan 243032 China

Efficient tandem reactions on a single catalytic nanostructure would be beneficial to improving chemical transformation efficiency and reducing safety implications. It is imperative to identify the active sites for each single step reaction so that the entire reaction process can be optimized by designing and integrating the sites. Herein, hydrogen transfer reaction is taken as a proof-of-concept demonstration to show that the spatial integration of active sites is important to the catalytic efficiency of the entire process in tandem reactions. We identified specific active sites (i.e., various sites at faces versus corners and edges) for formic acid decomposition and alkene/nitrobenzene hydrogenation-the two steps in hydrogen transfer reactions, by employing three different shapes of Pd nanocrystals in tunable sizes. The investigation reveals that the decomposition of formic acid occurs preferentially at the edge sites of cubic nanocrystal and the plane sites of octahedral/ tetrahedral nanocrystals, while the hydrogenation takes place mainly at the edge sites of both cubic and octahedral/ tetrahedral nanocrystals. The consistency of active edge sites during different step reactions enables cubic nanocrystals to exhibit a higher activity than octahedral nanocrystals in hydrogen transfer reactions, although octahedrons offer comparable activities to cubes in formic acid decomposition and hydrogenation reactions. Guided by these findings, we further improved the overall performance of tandem catalysis by specifically promoting the limiting step through nanocatalyst design. This work provides insights into the rational design of heterogeneous nanocatalysts in tandem reactions.

关键词： hydrogen transfer reaction palladium tandem reaction reactive site hydrogenation

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Optimizing geometric configuration of single Zn-N_(4) sites for boosting reciprocal transformation between aromatic alcohols and aldehydes

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Nano Research 2023年第7期16卷 9132-9141页

作者： Shengjie Wei Yucheng Jin Chunlin Lv Chao Lian Zheng Chen Xiao Liang Qinghua Zhang Xin Chen Dongdong Qi Zhi Li School of Materials Science and Engineering Nankai UniversityTianjin 300350China Department of Chemistry Tsinghua UniversityBeijing 100084China Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials Department of ChemistryUniversity of Science and Technology BeijingBeijing 100083China School of Pharmacy and Center on Translational Neuroscience Minzu University of ChinaBeijing 100081China Department of Chemistry School of ScienceBeijing Jiaotong UniversityBeijing 100091China School of Chemistry and Materials Science Anhui Normal UniversityWuhu 241002China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Solid State ChemistryUniversity of Science and Technology BeijingBeijing 100083China College of Chemistry Beijing Normal UniversityBeijing 100875China

It is significant to optimize geometric configuration of metal catalytic sites and boost their catalytic ***,we synthesized isolated single Zn-N_(4)sites on N-doped carbon(Zn-CN)by pyrolyzing zeolite imidazole framework-8(ZIF-8)at different *** the reciprocal transformation between benzyl alcohol and benzaldehyde,the catalytic activities of Zn-CN catalysts exhibited a volcano-like trend as the pyrolysis temperatures *** optimal catalyst was Zn-CN-900,with outstanding catalytic activity exceeding commercial 20 wt.%Pd/C and 20 wt.%Pt/C,promising to substitute the noble metalbased catalysts.X-ray absorption near-edge structure(XANES)measurements and density functional theory(DFT)calculation revealed the gradual transformation from tetrahedral ZnN_(4)sites of ZIF-8 into planar ZnN_(4)sites above 700℃,with the maximum planar ZnN_(4)sites in *** stronger adsorption between reactants and planar ZnN_(4)sites facilitated the activation of reactants compared with tetrahedral ZnN_(4)*** work will provide valuable insight into rational design of efficient catalysts by optimizing geometric configuration of catalytic sites.

关键词： geometric configuration single Zn-N_(4)sites benzyl alcohol oxidation hydrogen transfer reaction

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Bis(ortho-)chelated Monoanionic Bisphosphinoaryl Ruthenium(II) Complexes: Synthesis, Characterization and Reactivity

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Chinese Journal of Chemistry 2002年第3期20卷 207-213页

作者： van KLINK Gerard P. M DANI Paulo van KOTEN Gerard Department of Metal-Mediated Synthesis Debye Institute Utrecht UniversityDepartment of Metal-Mediated Synthesis Debye Institute Utrecht UniversityDepartment of Metal-Mediated Synthesis Debye Institute Utrecht University Padualaan 8 3584 CH Utrech

Bisphosphinoaryl ruthenium(Ⅱ) compounds are synthesized using two distinctsynthetic routes. One route, direct cycloruthenation, consists of the reaction of the parent arenecompound R-PCHP with [RuCl_2 (PPh_3)_3] in chlorinated solvents. However, this route suffers frommajor drawbacks because HCl is formed as well as free triphenylphoshine. The other route, thetranscyclometalation reaction, involves the interconversion of one cyclometalated ligand metalcomplex, [RuCl (NCN) (PPh_3)], into another complex, [RuCl (R-PCP) (PPh_3)], with concomitantconsumption and formation of the corresponding arenes R-PCHP and NCHN, respectively.

关键词： ruthenium transcyclometalation reaction monoanionic terdentate P, C,P′-bisphosphinoaryl hydrogen transfer reaction

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Catalyst Innovation for Reducing Olefin Content in MGG Gasoline

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China Petroleum Processing & Petrochemical Technology 2010年第2期12卷 19-21页

作者： Yu Daping Qiu Zhonghong SINOPEC Catalyst Company Qilu Division Zibo 255300 SINOPEC Research Institute of Petroleum Processing

In order to reduce the olefin content in gasoline manufactured by the MGG （Maximizing Liquefied Gas and Gasoline） process while retaining the LPG yield, RIPP has developed a novel catalyst consisting of a more pore-opened matrix and the modified Y-zeolite and the ZRP zeolite modified with metal oxides. Test results have revealed that compared with the commercial catalyst RAG under comparable reaction conditions the reaction conversion rate and product distribution provided by the novel catalyst were similar, but the olefin content in gasoline obtained thereof was decreased with the octane rating unchanged along with a slight reduction of olefin content in the LPG fraction. The hydrothermal stability of the novel catalyst was better than the commercial catalyst RAG.

关键词： catalyst gasoline octane hydrogen transfer reaction olefin selectivity

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A MoS_2 nanocatalyst with surface-enriched active sites for the heterogeneous transfer hydrogenation of nitroarenes

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Chinese Journal of Catalysis 2018年第1期39卷 79-87页

作者： Jia Wang Yajie Zhang Jiangyong Diao Jiayun Zhang Hongyang Liu Dangsheng Su Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 Liaoning China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000Gansu China School of Materials Science and Engineering University of Science and Technology of China Shenyang 110016 Liaoning China Energy Research Resources Division Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of SciencesDalian 116023 Liaoning China

A highly efficient and reusable plane‐curved and interlayer‐expanded MoS2nanocatalyst with increased exposure of active sites was *** catalyst was used for the heterogeneous hydrogen transfer reaction of nitroarenes with hydrazine monohydrate as a reductant under mild reaction conditions without pressure and base,which was different from other hydrogen transfer systems that require the presence of a base(e.g.,propan‐2‐ol/KOH).The sandwiching of carbon between the MoS2nanosheets increased the distance between the layers of MoS2and exposed more Mo sites,resulting in superior catalytic performance compared with that of bulk *** active hydrogen(H*)generated from N2H4could directly transfer to the–NO2groups of nitrobenzene to form aniline followed by N2emission,which was confirmed by detecting the gas emission with mass spectrometry during the decomposition of hydrazine or the co‐existence of nitrobenzene and hydrazine.?2018,Dalian Institute of Chemical Physics,Chinese Academy of *** by Elsevier *** rights reserved.

关键词： Molybdenum disulfide Interlayer expansion hydrogen transfer reaction Nitrobenzene reduction Alkali‐free

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Changing the balance of the MTO reaction dual-cycle mechanism: reactions over ZSM-5 with varying contact times

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Chinese Journal of Catalysis 2016年第8期37卷 1413-1422页

作者：张默之徐舒涛魏迎旭李金哲王金棒张雯娜高树树刘中民中国科学院大连化学物理研究所洁净能源国家实验室(筹)甲醇制烯烃国家工程实验室能源材料化学协同创新中心辽宁大连116023 中国科学院大学北京100049 中国科学院大连化学物理研究所催化基础国家重点实验室辽宁大连116023

The methanol to olefins （MTO） reaction was performed over ZSM‐5 zeolite at 300℃ under various methanol weight hourly space velocity （WHSV） values. During these trials, the catalytic perfor‐mance was assessed, in addition to the formation and function of organic compounds retained in the zeolite. Analysis of reaction effluents and confined organics demonstrated a dual‐cycle reaction mechanism when employing ZSM‐5. The extent of the hydrogen transfer reaction, a secondary reac‐tion in the MTO process, varied as the catalyst‐methanol contact time was changed. In addition, 12C/13C‐methanol switch experiments indicated a relationship between the dual‐cycle mechanism and the extent of the hydrogen transfer reaction. reactions employing a low methanol WHSV in conjunction with a long contact time favored the hydrogen transfer reaction to give alkene products and promoted the generation and accumulation of retained organic species, such as aromatics and methylcyclopentadienes, which enhance the aromatic cycle. When using higher WHSV values, the reduced contact times lessened the extent of the hydrogen transfer reaction and limited the genera‐tion of methylcyclopentadienes and aromatic species. This suppressed the aromatic cycle, such that the alkene cycle became the dominant route during the MTO reaction.

关键词： Methanol to olefins Dual-cycle mechanism ZSM-5 Contact time hydrogen transfer reaction

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