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Formaldehyde intermediate participating in the conversion of methanol to aromatics over zinc modified H-ZSM-5

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Journal of Energy Chemistry 2021年第3期30卷 174-178页

作者： Youming Ni Wenliang Zhu Zhongmin Liu National Engineering Laboratory for Methanol to Olefins Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Metal-modified H-ZSM-5 has a high selectivity of aromatics in methanol to aromatics(MTA)reaction,which is often attributed to the metal promoting the aromatization of intermediate ***,the effect of methanol dehydrogenation on aromatics formation over these catalysts is rarely ***,we report that HCHO,which is formed by methanol dehydrogenation over Zn/H-ZSM-5 prepared by Zn impregnation,can participate in the synthesis of *** conversion can produce more aromatics than olefins(propylene or ethylene)conversion over Zn/H-ZSM-5,indicating the conventional MTA pathway including methanol-to-olefins and olefins-to-aromatics is not ***,an MTA mechanism including the conventional pathway and the methanol and HCHO coupling pathway is systematically proposed.

关键词： Methanol Formaldehyde Aromatics Zn H-ZSM-5

Single-atom catalysis:a promising avenue for precisely controlling reaction pathways

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Frontiers of chemical Science and Engineering 2024年第7期18卷 97-120页

作者： Xiaobo Yang Xuning Li Yanqiang Huang State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Single-atom catalysts (SACs), characterized by exceptionally high atom efficiency, have garnered significant attention across various catalytic reactions. Recent studies have showcased SACs with robust capabilities for precise catalysis, specifically targeting reactions along designated pathways. This review focuses on the advances in the precise activation and reconstruction of chemical bonds on SACs, including precise activation of C–O and C–H bonds and selective couplings involving C–C and C–N bonds. Our discussion begins with a thorough exploration of the factors that render SACs skilled in precise catalytic processes, encompassing the narrow d-band electronic state of single atom site resulting in the adsorption tendency, isolate site resulting in unique adsorption structure, and synergy effect of a single atom site with its neighbors. Subsequently, we elaborate on the applications of SACs in electrocatalysis and thermocatalysis including four prominent reactions, namely, electrochemical CO_(2) reduction, urea electrochemical synthesis, CO_(2) hydrogenation, and CH4 activation. Then the concept of rational design of SACs for precisely controlling reaction pathways is discussed from the aspects of pore structure design, support-metal strong interaction, and support hydrophilic/hydrophobic. Finally, we summarize the challenges encountered by SACs in the field of precise catalytic processes and outline prospects for their further development in this domain.

关键词： single atom catalysts selective oxidation CO_(2)RR bond coupling

One-pot remote desymmetrization/Peterson-olefination for the construction of silicon-stereogenic silyl ethers

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Science China Chemistry 2023年第10期66卷 2797-2802页

作者： Wengang Guo Qian Li Yan Liu Can Li State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Chiral silyl ethers and silanols are important synthetic intermediates and bioactive *** this work,we developed a onepot remote desymmetrization/Peterson-olefination of silacyclopentene oxides with benzoic acids in the presence of Martin’s *** new methodology not only realizes the atom-economy of Peterson olefination,but also represents a catalytic method for synthesis of silicon-stereogenic silyl *** a bulky chiral phosphoric acid 4i as organocatalyst,the reactions proceeded efficiently to afford various olefin-functionalized organosilyl ethers in excellent diastereoelectivities(up to 25/1 d.r.)and high enantioselectivities(up to 94%ee).

关键词： asymmetric catalysis silicon-stereogenic silyl ether remote desymmetrization/Peterson-olefination bronsted acid catalysis

Monitoring gas-and particulate-phase short-chain polychlorinated paraffins in the urban air of dalian by a self-developed passive sampler

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Journal of Environmental Sciences 2019年第6期31卷 287-295页

作者： Yifan Wang Xiuhua Zhu Yuan Gao Hao Bai Pengyuan Wang Jiping Chen Heping Yuan Longxing Wang Xiaoxiao Li Wei Wang School of Environmental and chemical Engineering Dalian Jiaotong University dalian institute of chemical physics Chinese Academy of Sciences College of Chemistry Jilin University dalian Meteorological Observatory

The concentration of short-chain polychlorinated paraffins(SCCPs) in the urban air of dalian,China was monitored from September 2016 to August 2017 with a self-developed passive sampler(PAS1) and an active high-volume sampler, simultaneously. PAS1 successfully collected the entire target SCCPs in the ambient air. Air SCCPs sampled by PAS1 were found be in the linear uptake stage during 181 days of sampling. Passive and active samples showed comparable congener profiles, and the dominant contributors of SCCPs in the two kinds of samples were similar. A significant linear correlation was observed between the total concentration of SCCPs sampled by PAS1 and active sampler in the four seasons. The passive sampling rates of the PAS1 for the gas and particulate phases of SCCPs were measured. The quantitative structure–property relationship of the sampling rate of PAS1(Rair) for gas-phase SCCPs was studied. From the molecular point of view, Rairwas mainly affected by the molecular weight and sub-cooled liquid vapor pressure of SCCPs. In general, SCCPs in the urban air of dalian mainly existed in gas phase,lower molecular weight SCCPs primarily occurred in the gas phase, whereas higher molecular weight SCCPs were predominately adsorbed or absorbed on airborne particles. The air concentration of SCCPs in the four seasons were different, the correlation of the concentration of SCCPs in the air with the meteorology parameters was conducted. The exposure risk by intake air SCCPs of the residents around the sampling sites was evaluated according to the European risk assessment standards.

关键词： Ambient air Short-chain polychlorinated paraf fins Passive sampler Active sampling Passive sampling

Structural reconstruction of Sn-based metal-organic frameworks for efficient electrochemical CO_(2) reduction to formate

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Chinese Journal of chemical Engineering 2022年第3期35卷 353-359页

作者： Yachen Deng Shifu Wang Yanqiang Huang Xuning Li State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

MOF-based materials have been widely explored in electrochemical CO_(2)reduction reactions for the production of valuable *** the reconstruction of those catalysts under working conditions is crucial for the identification of active sites and clarification of reaction ***,a series of six N coordinated Sn-based metal-organic frameworks(Sn-N6-MOFs)are newly developed for electrochemical CO_(2)reduction(CO_(2)RR).2%Sn-N6-MOF achieves the optimal catalytic performance with a formate Faradaic efficiency of~85%and a current density of 23 mA·cm^(-2) at-1.23 V ***-situ Raman results combined with ex-situ ^(119)Sn Mössbauer measurements reveal the structural reconstruction of Sn-N6-MOFs during CO_(2)RR,generating tin nanoclusters as the real active sites for CO_(2)electroreduction to HCOOH.

关键词： Structural reconstruction Metal-organic frameworks Mössbauer spectroscopy Electrochemical CO_(2)reduction

AN ADIABATIC CALORIMETER FOR HEAT- CAPACITY MEASUREMENTS FROM 80 TO 400K——HEAT CAPACITIES OF a-ALUMINA AND n-HEPTANE

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Science China Chemistry 1983年第10期26卷 1014-1026页

作者：谭志诚周立幸陈淑霞尹安学孙毅叶锦春王秀坤 dalian Academia Sinica dalian institute of chemical physics

An improved automatic adiabatic calorimeter for precision measurement of heat capacities of solid and liquid phases in the temperature range 80-400 K is described. Temperature control of the shield and electrical energy measurement are automated; data processing is performed by an electronic computer. The calorimeter proper has thin L-shaped vanes which make no contact with its inner wall and a device for helium filling, which greatly improves the internal thermal equilibration and effectively reduces the surface temperature gradient. Measurements of the heat capacities of a-alumina and n-heptane, two internationally accepted heat-capacity standards, show a precision of±0.1%, agree with those of the National Bureau of Standards (NBS) within ±0.2%, and demonstrate the reliability of the apparatus.

关键词： heat HEAT CAPACITIES OF a-ALUMINA AND n-HEPTANE AN ADIABATIC CALORIMETER FOR HEAT CAPACITY MEASUREMENTS FROM 80 TO 400K

Ordered cone-structured tin directly grown on carbon paper as efficient electrocatalyst for CO_(2) electrochemical reduction to formate

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Journal of Energy Chemistry 2021年第4期30卷 236-243页

作者： Hexiang Zhong Yanling Qiu Xianfeng Li Liwei Pan Huamin Zhang College of Environmental and chemical Engineering Dalian UniversityDalian 116622LiaoningChina Division of Energy Storage Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

The conversion of carbon dioxide to chemicals by the electrochemical reactions(ERC)is an efficient solution to the current energy crisis and excess CO_(2) *** is still a great challenge and of significance to synthesize a highly selective,efficient,and non-noble metal electrocatalyst that facilitates the ERC reaction.A novel triton X-100(C_(14)H_(22)O(C_(2)H_(4)O)n)assisted electrodeposition method was developed to synthesize the ordered cone-structured tin(OCSn)electrocatalysts with controllable morphology and *** results suggest that Triton X-100 plays an important role in directing the structure of the Sn electrocatalysts during the electrodeposition *** OCSn synthesized at 60 m A cm^(-2) achieves the best *** selectively catalyzes the ERC on the onset potential about 110 m V lower than Sn synthesized without Triton *** 0.5 M Na HCO_(3),high faradaic efficiency(92%)for formate product on OCSn has been *** prominently,the catalyst presents excellent stability,showing no performance deterioration during 30 h *** work provides an efficient,green,and scalable synthesis method of the electrocatalyst for CO_(2) reduction to formate.

关键词： CO_(2)electrochemical reduction CO2 emission reduction Ordered cone-structure tin(OCSn) Electro-deposition

Wormholelike mesoporous carbon supported Pt Ru catalysts toward methanol electrooxidation

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Journal of Energy Chemistry 2017年第1期26卷 200-206页

作者： Weifeng Liu Xiaoping Qin Xiongfu Zhang Zhigang Shao Baolian Yi State Key Laboratory of Fine chemicals School of Chemical Engineering Dalian University of Technology dalian institute of chemical physics Chinese Academy of Sciences

Wormholelike mesoporous carbons (WMCs) with three different pore diameters (D-P), namely WMC-F7 (D-p = 8.5 nm), WMC-F30 (D-p =4.4 nm), and WMC-F0 (D-p =3.1 nm) are prepared via a modified sol-gel process. Then PtRu nanoparticles with the particle size (40 of 3.2 nm supported on WMCs are synthesized with a modified pulse microwave-assisted polyol method. It is found that the pore diameter of WMCs plays an important role in the electrochemical activity of PtRu toward alcohol electrooxidation reaction. PtRu/WMC-F7 with D-p > 2d(pt) exhibits the largest electrochemical surface area (ESA) and the highest activity toward methanol electrooxidation. With the decrease in Dp, PtRu/WMC-F30 and PtRu/WMC-F0 have much lower ESA and electrochemical activity, especially for the isopropanol electrooxidation with a larger molecular size. When D-p is more than twice d(pt), the mass transfer of reactants and electrolyte are easier, and thus more PtRu nanoparticles can be utilized and the catalysts activity can be enhanced. (C) 2016 Science Press and dalian institute of chemical physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

关键词： Wormholelike mesoporous carbon PtRu catalyst Pore diameter Methanol electrooxidation

Microemulsion-mediated hydrothermal synthesis of flower- like MoS2 nanomaterials with enhanced catalytic activities for anthracene hydrogenation

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Frontiers of chemical Science and Engineering 2018年第1期12卷 32-42页

作者： Yuxia Jiang Donge Wang Zhendong Pan Huaijun Ma Min Li Jiahe Li Anda Zheng Guang Lv Zhijian Tian dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

Flower-like intercalated MoS2 nanomaterials have been successfully synthesized via a microemulsion- mediated hydrotherrnal （MMH） method, and characterized by X-ray diffraction, Raman spectroscopy, element analysis, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy in detail. Their catalytic performance for anthracene hydrogenation was evaluated using a slurry-bed batch reactor with an initial hydrogen pressure of 80 bar at 350 ℃ for 4 h. The intercalated MoS2 nanoflowers synthesized from Na2MoO4 （MoS2-S） and H2MoO4 （MoS2-A） as molybde- num precursors have diameters of about 150 and 50 nm, respectively. MoS2 nanosheets on MoS2-S and MoS2-A possess stacking layer numbers of 5-10 and 2-5, and slab lengths of about 15 and 10 nm, respectively. The interlayer distances of MoS2-S and MoS2-A are both enlarged from 0.62 nm to about 0.95 nm due to the intercalation ofNH4＋ and surfactant molecules. The MoS2 nanoflowers have high catalytic activities for anthracene hydrogenation. The selectivity for octahydroanthracene, a deeply hydrogenated product, over MoS2-A is 89.8%, which is 31.0 times higher than that over commercial bulk MoS2. Fully hydrogenated product （perhydroanthracene） was also detected over MoS2 nanoflowers with a selectivity of 3.7%. The enhanced hydrogenation activities of MoS2 nanoflowers can be ascribed to the high exposure of catalytic active sites, resulting from the smaller particle size, fewer stacking layer, shorter slab length and enlarged interlayer distance of MoS2 nanoflowers compared with commercial bulk MoS2. In addition, a possible growth mechanism of MoS2 nanoflowers synthesized via the MMH method was proposed.

关键词： microemulsion intercalated MoS2 catalytic hydrogenation active sites