1
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Li H, Zheng L, Lu Q, Li Z, Wang X. A monolayer crystalline covalent network of polyoxometalate clusters. SCIENCE ADVANCES 2023; 9:eadi6595. [PMID: 37436995 DOI: 10.1126/sciadv.adi6595] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 06/08/2023] [Indexed: 07/14/2023]
Abstract
Monolayer two-dimensional (2D) materials are of great interest because of their unique electronic structures, noticeable in-plane confinement effect, and exceptional catalytic properties. Here, we prepared 2D covalent networks of polyoxometalate clusters (CN-POM) featuring monolayer crystalline molecular sheets, formed by the covalent connection between tetragonally arranged POM clusters. The CN-POM shows a superior catalytic efficiency in the oxidation of benzyl alcohol, and the conversion rate is five times higher than that of the POM cluster units. Theoretical calculations show that in-plane electron delocalization of CN-POM contributes to easier electron transfer and increases catalytic efficiency. Moreover, the conductivity of the covalently interconnected molecular sheets was 46 times greater than that of individual POM clusters. The preparation of monolayer covalent network of POM clusters provides a strategy to synthesize advanced cluster-based 2D materials and a precise molecular model to investigate the electronic structure of crystalline covalent networks.
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Affiliation(s)
- Haoyang Li
- Engineering Research Center of Advanced Rare Earth Materials, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lirong Zheng
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Qichen Lu
- Engineering Research Center of Advanced Rare Earth Materials, Department of Chemistry, Tsinghua University, Beijing 100084, China
- Huaneng Clean Energy Research Institute, Beijing 102209, China
| | - Zhong Li
- Engineering Research Center of Advanced Rare Earth Materials, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Xun Wang
- Engineering Research Center of Advanced Rare Earth Materials, Department of Chemistry, Tsinghua University, Beijing 100084, China
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2
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Yu X, Deng J, Liu Y, Jing L, Gao R, Hou Z, Zhang Z, Dai H. Enhanced Water Resistance and Catalytic Performance of Ru/TiO 2 by Regulating Brønsted Acid and Oxygen Vacancy for the Oxidative Removal of 1,2-Dichloroethane and Toluene. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11739-11749. [PMID: 35880312 DOI: 10.1021/acs.est.2c03336] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The compositions of volatile organic compounds (VOCs) under actual industrial conditions are often complex; especially, the interaction of intermediate products easily leads to more toxic emissions that are harmful to the atmospheric environment and human health. Herein, we report a comparative investigation on 1,2-dichloroethane (1,2-DCE) and (1,2-DCE + toluene) oxidation over the Ru/TiO2, phosphotungstic acid (HPW)-modified Ru/TiO2, and oxygen vacancy-rich Ru/TiOx catalysts. The doping of HPW successfully introduced the 1,2-DCE adsorption sites to promote its oxidation and exhibited outstanding water resistance. For the mixed VOCs, Ru/HPW-TiO2 promoted the preferential and superfluous adsorption of toluene and resulted in the inhibition of 1,2-DCE degradation. Therefore, HPW modification is a successful strategy in catalytic 1,2-DCE oxidation, but Brønsted acid sites tend to adsorb toluene in the mixed VOC oxidation. The Ru/TiOx catalyst exhibited excellent activity and stability in the oxidation of mixed VOCs and could inhibit the generation of byproducts and Cl2 compared with the Ru/HPW-TiO2 catalyst. Compared with the Brønsted acid modification, the oxygen vacancy-rich catalysts are significantly suitable for the oxidation of multicomponent VOCs.
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Affiliation(s)
- Xiaohui Yu
- Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Laboratory of Catalysis Chemistry and Nanoscience, Department of Environmental Chemical Engineering, College of Environmental and Chemical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Jiguang Deng
- Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Laboratory of Catalysis Chemistry and Nanoscience, Department of Environmental Chemical Engineering, College of Environmental and Chemical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Yuxi Liu
- Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Laboratory of Catalysis Chemistry and Nanoscience, Department of Environmental Chemical Engineering, College of Environmental and Chemical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Lin Jing
- Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Laboratory of Catalysis Chemistry and Nanoscience, Department of Environmental Chemical Engineering, College of Environmental and Chemical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Ruyi Gao
- Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Laboratory of Catalysis Chemistry and Nanoscience, Department of Environmental Chemical Engineering, College of Environmental and Chemical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Zhiquan Hou
- Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Laboratory of Catalysis Chemistry and Nanoscience, Department of Environmental Chemical Engineering, College of Environmental and Chemical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Zexu Zhang
- Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Laboratory of Catalysis Chemistry and Nanoscience, Department of Environmental Chemical Engineering, College of Environmental and Chemical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Hongxing Dai
- Beijing Key Laboratory for Green Catalysis and Separation, Key Laboratory of Beijing on Regional Air Pollution Control, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Laboratory of Catalysis Chemistry and Nanoscience, Department of Environmental Chemical Engineering, College of Environmental and Chemical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
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3
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Wachs IE. Progress in Catalysis by Mixed Oxides: From Confusion to Catalysis Science. Catal Today 2022. [DOI: 10.1016/j.cattod.2022.08.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Tao M, Ishikawa S, Zhang Z, Murayama T, Inomata Y, Kamiyama A, Nakaima I, Jing Y, Mine S, Shimoda K, Toyao T, Shimizu KI, Ueda W. Synthesis of Zeolitic Ti, Zr-Substituted Vanadotungstates and Investigation of Their Catalytic Activities for Low Temperature NH 3-SCR. ACS Catal 2021. [DOI: 10.1021/acscatal.1c04086] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Meilin Tao
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
| | - Satoshi Ishikawa
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
| | - Zhenxin Zhang
- School of Material Science and Chemical Engineering, Ningbo University, Fenghua Road 818, Ningbo, Zhejiang 315211, P. R. China
| | - Toru Murayama
- Research Center for Gold Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Yusuke Inomata
- Research Center for Gold Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Akiho Kamiyama
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
| | - Ichika Nakaima
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
| | - Yuan Jing
- Institute for Catalysis, Hokkaido University, N-21, W-10 Kita-Ku, Sapporo 001-0021, Japan
| | - Shinya Mine
- Institute for Catalysis, Hokkaido University, N-21, W-10 Kita-Ku, Sapporo 001-0021, Japan
| | - Kosuke Shimoda
- Institute for Catalysis, Hokkaido University, N-21, W-10 Kita-Ku, Sapporo 001-0021, Japan
| | - Takashi Toyao
- Institute for Catalysis, Hokkaido University, N-21, W-10 Kita-Ku, Sapporo 001-0021, Japan
- Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Kyoto Daigaku Katsura,
Nishikyo-ku, Kyoto 615-8520, Japan
| | - Ken-ichi Shimizu
- Institute for Catalysis, Hokkaido University, N-21, W-10 Kita-Ku, Sapporo 001-0021, Japan
- Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Kyoto Daigaku Katsura,
Nishikyo-ku, Kyoto 615-8520, Japan
| | - Wataru Ueda
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
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5
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Beni ZH, Albadi J, Kiyani H. Preparation, characterization and catalytic study of a nano-inorganic composite of CuO/NiO for the regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles in water. INORG NANO-MET CHEM 2021. [DOI: 10.1080/24701556.2021.1983838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Zohreh Hashemi Beni
- Department of Chemistry, Faculty of Science, Shahrekord University, Shahrekord, Iran
| | - Jalal Albadi
- Department of Chemistry, Faculty of Science, Shahrekord University, Shahrekord, Iran
| | - Hamzeh Kiyani
- Department of Chemistry, Faculty of Science, Shahrekord University, Shahrekord, Iran
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6
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Shimoda K, Ishikawa S, Matsumoto K, Miyasawa M, Takebe M, Matsumoto R, Lee S, Ueda W. Nb−V Mixed Oxide with a Random Assembly of Pentagonal Units: A Catalyst for Oxidative Dehydrogenation of Ethane and Propane. ChemCatChem 2021. [DOI: 10.1002/cctc.202100463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Kosuke Shimoda
- Department of Material and Life Chemistry Faculty of Engineering Kanagawa University 3–27 Rokkakubashi Kanagawa-ku Yokohama 221-8686 Japan
| | - Satoshi Ishikawa
- Department of Material and Life Chemistry Faculty of Engineering Kanagawa University 3–27 Rokkakubashi Kanagawa-ku Yokohama 221-8686 Japan
| | - Katsuya Matsumoto
- Department of Material and Life Chemistry Faculty of Engineering Kanagawa University 3–27 Rokkakubashi Kanagawa-ku Yokohama 221-8686 Japan
| | - Mai Miyasawa
- Department of Material and Life Chemistry Faculty of Engineering Kanagawa University 3–27 Rokkakubashi Kanagawa-ku Yokohama 221-8686 Japan
| | - Marino Takebe
- Department of Material and Life Chemistry Faculty of Engineering Kanagawa University 3–27 Rokkakubashi Kanagawa-ku Yokohama 221-8686 Japan
| | - Riku Matsumoto
- Department of Material and Life Chemistry Faculty of Engineering Kanagawa University 3–27 Rokkakubashi Kanagawa-ku Yokohama 221-8686 Japan
| | - Syutoku Lee
- Department of Material and Life Chemistry Faculty of Engineering Kanagawa University 3–27 Rokkakubashi Kanagawa-ku Yokohama 221-8686 Japan
| | - Wataru Ueda
- Department of Material and Life Chemistry Faculty of Engineering Kanagawa University 3–27 Rokkakubashi Kanagawa-ku Yokohama 221-8686 Japan
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7
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Synthesis, physical and photo-electrochemical characterizations of a new hybrid host-guest complex [Cu12(C2N3H2)8Cl][(PW12O40)]. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129718] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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Divanadium substituted keggin [PV2W10O40] on non-reducible supports-Al2O3 and SiO2: synthesis, characterization, and catalytic properties for oxidative dehydrogenation of propane. REACTION KINETICS MECHANISMS AND CATALYSIS 2020. [DOI: 10.1007/s11144-020-01893-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Effects of support and reaction pressure for the synthesis of dimethyl ether over heteropolyacid catalysts. Sci Rep 2020; 10:8551. [PMID: 32444653 PMCID: PMC7244519 DOI: 10.1038/s41598-020-65296-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/27/2020] [Indexed: 11/08/2022] Open
Abstract
Dimethyl ether (DME) is an advanced second-generation biofuel produced via methanol dehydration over acid catalysts such as γ-Al2O3, at temperatures above 240 °C and pressures above 10 bar. Heteropolyacids such as tungstosilicic acid (HSiW) are Brønsted acid catalysts with higher DME production rates than γ-Al2O3, especially at low temperatures (140–180 °C). In this work, we show that the performance of supported HSiW for the production of DME is strongly affected by the nature of the support. TiO2 and SiO2 supported HSiW display the highest DME production rates of ca. 50 mmolDME/h/gHSiW. Characterization of acid sites via 1H-NMR, NH3-isotherms and NH3-adsrobed DRIFT reveal that HSiW/X have Brønsted acid sites, HSiW/TiO2 showing more and stronger sites, being the most active catalyst. Methanol production increases with T until 200 °C where a rapid decay in methanol conversion is observed. This effect is not irreversible, and methanol conversion increases to ca. 90% by increasing reaction pressure to 10 bar, with DME being the only product detected at all reaction conditions studied in this work. The loss of catalytic activity with the increasing temperature and its increasing with reaction pressure accounts to the degree of contribution of the pseudo-liquid catalysis under the reaction conditions studied.
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10
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Hirakawa T, Shimokawa Y, Tokuzumi W, Sato T, Tsushida M, Yoshida H, Hinokuma S, Ohyama J, Machida M. Multicomponent Spinel Oxide Solid Solutions: A Possible Alternative to Platinum Group Metal Three-Way Catalysts. ACS Catal 2019. [DOI: 10.1021/acscatal.9b03772] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | - Hiroshi Yoshida
- Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, 1-30 Goryo-Ohara, Nishikyo, Kyoto 615-8245, Japan
| | - Satoshi Hinokuma
- Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, 1-30 Goryo-Ohara, Nishikyo, Kyoto 615-8245, Japan
| | - Junya Ohyama
- Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, 1-30 Goryo-Ohara, Nishikyo, Kyoto 615-8245, Japan
| | - Masato Machida
- Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, 1-30 Goryo-Ohara, Nishikyo, Kyoto 615-8245, Japan
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11
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Sahoo D, Patnaik S, Parida K. Construction of a Z-Scheme Dictated WO 3-X /Ag/ZnCr LDH Synergistically Visible Light-Induced Photocatalyst towards Tetracycline Degradation and H 2 Evolution. ACS OMEGA 2019; 4:14721-14741. [PMID: 31552311 PMCID: PMC6756545 DOI: 10.1021/acsomega.9b01146] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 07/08/2019] [Indexed: 05/19/2023]
Abstract
Herein, we have designed nonstoichiometric WO3, coupled with ZnCr layered double hydroxide (LDH) nanosheeet through Ag nanoparticle as the solid-state electron mediator to form WO3-X /Ag/ZnCr LDH Z-scheme photocatalyst. The presence of oxygen defect levels in as-synthesized materials was confirmed by Raman, X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) analyses. The photocatalytic performance of the catalysts was investigated by the tetracycline degradation and H2 energy production under visible light irradiation. The WO3-X /Ag/ZnCr LDH ternary heterostructure exhibits superior activity toward tetracycline degradation and hydrogen evolution. The excellent photocatalytic performance of the catalyst was attributed to the synergistic effects among three species (WO3-X , Ag, and ZnCr LDH) and the enhanced separation efficiency of photoinduced charge carriers through the Z-scheme WO3-X /Ag/ZnCr LDH system. In addition, the created oxygen deficiency on WO3-X could improve the photocatalytic behavior of ZnCr LDH in heterostructure by delaying the recombination efficiency of photoexcited electron-hole pairs. Furthermore, the higher affinity of tetracycline at the oxygen defect levels of the photocatalyst supports the high rate of tetracycline degradation. The enhanced photocatlytic activity of the catalysts was further supported by PL spectra and photoelectrochemical studies (electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) plot). The present research opens up a new strategy for designing highly efficient visible light-induced Z-scheme-based photocatalysts with high population of active sites for energy and environmental applications in a sustainable manner.
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12
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Heteropolyacid Salt Catalysts for Methanol Conversion to Hydrocarbons and Dimethyl Ether: Effect of Reaction Temperature. Catalysts 2019. [DOI: 10.3390/catal9040320] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Phosphotungstic and silicotungstic acid salt catalysts (CuPW, CuSiW, FePW, FeSiW) were synthesized by substitution of protons with ferric and copper ions through a simple replacement reaction. The structure and thermal stability were characterized by IR, XRD and TG, and the salts showed a keggin structure and a thermal tolerance near 450 °C. Temperature programmed reactions indicated that the four catalysts showed similar trends in the change of methanol conversion, DME selectivity, and light olefins selectivity at 100–400 °C. Copper salt catalysts showed a 100% DME selectivity at temperatures ranging from 100–250 °C, while FeSiW and FePW catalysts had a 100% DME selectivity near 250 °C. Moreover, the heteropolyacid salt catalysts also produced a certain number of light olefins at the temperature ranging from 250–350 °C, and the CuSiW catalyst exhibited the highest ethylene and propylene selectivity of 44%. In the stability test evaluated at 200 °C, the catalysts showed different tendencies during the induction period and the same trends during the reduction period for the methanol conversion to DME, due to the differences in the strengths of the strong acid sites. Finally, the silicotungstic acid salt catalysts showed the longest lifetime of 120 h, much longer than the heteropolyacids. This approach provides an effective way to synthesize hydrocarbons through methanol, especially DME, at different temperatures using one catalyst.
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13
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Chu YJ, Chen XM, Liu CG. Computational study on epoxidation of propylene by dioxygen using the silanol-functionalized polyoxometalate-supported osmium oxide catalyst. Inorg Chem Front 2019. [DOI: 10.1039/c9qi00900k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The silanol-functionalized POM-supported single-site Os oxide catalyst has been theoretically considered for epoxidation of propylene in the presence of dioxygen based on density functional theory calculations.
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Affiliation(s)
- Yun-Jie Chu
- Department of Chemistry
- Faculty of Science
- Beihua University
- Jilin City
- P. R. China
| | - Xue-Mei Chen
- College of Chemical Engineering
- Northeast Electric Power University
- Jilin City
- P. R. China
| | - Chun-Guang Liu
- Department of Chemistry
- Faculty of Science
- Beihua University
- Jilin City
- P. R. China
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14
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Zhang W, Innocenti G, Oulego P, Gitis V, Wu H, Ensing B, Cavani F, Rothenberg G, Shiju NR. Highly Selective Oxidation of Ethyl Lactate to Ethyl Pyruvate Catalyzed by Mesoporous Vanadia-Titania. ACS Catal 2018. [PMID: 29527403 PMCID: PMC5839604 DOI: 10.1021/acscatal.7b03843] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
The
direct oxidative dehydrogenation of lactates with molecular
oxygen is a “greener” alternative for producing pyruvates.
Here we report a one-pot synthesis of mesoporous vanadia–titania
(VTN), acting as highly efficient and recyclable catalysts for the
conversion of ethyl lactate to ethyl pyruvate. These VTN materials
feature high surface areas, large pore volumes, and high densities
of isolated vanadium species, which can expose the active sites and
facilitate the mass transport. In comparison to homogeneous vanadium
complexes and VOx/TiO2 prepared
by impregnation, the meso-VTN catalysts showed superior activity,
selectivity, and stability in the aerobic oxidation of ethyl lactate
to ethyl pyruvate. We also studied the effect of various vanadium
precursors, which revealed that the vanadium-induced phase transition
of meso-VTN from anatase to rutile depends strongly on the vanadium
precursor. NH4VO3 was found to be the optimal
vanadium precursor, forming more monomeric vanadium species. V4+ as the major valence state was incorporated into the lattice
of the NH4VO3-derived VTN material, yielding
more V4+–O–Ti bonds in the anatase-dominant
structure. In situ DRIFT spectroscopy and density functional theory
calculations show that V4+–O–Ti bonds are
responsible for the dissociation of ethyl lactate over VTN catalysts
and for further activation of the deprotonation of β-hydrogen.
Molecular oxygen can replenish the surface oxygen to regenerate the
V4+–O–Ti bonds.
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Affiliation(s)
- Wei Zhang
- Van
’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090GD Amsterdam, The Netherlands
| | - Giada Innocenti
- Dipartimento
di Chimica Industriale, ALMA MATER STUDIORUM Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
- Consorzio
INSTM, UdR di Bologna, Firenze, Italy
| | - Paula Oulego
- Department
of Chemical and Environmental Engineering, University of Oviedo, C/Julián Clavería, s/n., E-33071, Oviedo, Spain
| | - Vitaly Gitis
- Unit
of Environmental Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel
| | - Haihong Wu
- Shanghai
Key Laboratory of Green Chemistry and Chemical Processes, Department
of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, People’s Republic of China
| | - Bernd Ensing
- Van
’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090GD Amsterdam, The Netherlands
| | - Fabrizio Cavani
- Dipartimento
di Chimica Industriale, ALMA MATER STUDIORUM Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
- Consorzio
INSTM, UdR di Bologna, Firenze, Italy
| | - Gadi Rothenberg
- Van
’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090GD Amsterdam, The Netherlands
| | - N. Raveendran Shiju
- Van
’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090GD Amsterdam, The Netherlands
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15
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Meng J, Lin Q, Chen T, Wei X, Li J, Zhang Z. Oxygen vacancy regulation on tungsten oxides with specific exposed facets for enhanced visible-light-driven photocatalytic oxidation. NANOSCALE 2018; 10:2908-2915. [PMID: 29368784 DOI: 10.1039/c7nr08590g] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Introduced oxygen vacancy on WO3 with specific exposed facets was prepared through facile solvothermal treatment and different cooling methods. We demonstrated that the density of oxygen defects could be regulated by different cooling methods and speculated that oxygen vacancy with appropriate concentration range could promote photocatalytic activity through suppressing the recombination of photo-induced carriers. The specific exposed facets with higher oxidation efficiency were prepared by solvothermal reaction. WO3-A treated by air cooling exhibits the best photocatalytic oxygen evolution rate at 500 μmol g-1 h-1 using AgNO3 as sacrifice agent under visible light (λ > 400 nm) without any co-catalysts, which is about 2 times higher than WO3-N without oxygen defects. This strategy, using different cooling methods to regulate oxygen vacancy concentration on tungsten oxides, could contribute to the design of other high efficiency photocatalysts.
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Affiliation(s)
- Jie Meng
- Center of Electron Microscopy, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, PR China.
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16
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Fang L, Wang G, Guo W. Rational synthesis of core-shell Fe3O4@thermally crosslinked PANI nanostructures based on a PVP-mediated in-situ polymerization strategy: Towards a stable catalyst support for 12-tungstophosphoric acid. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.07.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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17
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Foo GS, Hu G, Hood ZD, Li M, Jiang DE, Wu Z. Kinetics and Mechanism of Methanol Conversion over Anatase Titania Nanoshapes. ACS Catal 2017. [DOI: 10.1021/acscatal.7b01456] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guo Shiou Foo
- Chemical
Sciences Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Guoxiang Hu
- Department
of Chemistry, University of California, Riverside, California 92521, United States
| | - Zachary D. Hood
- School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Meijun Li
- Chemical
Sciences Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - De-en Jiang
- Department
of Chemistry, University of California, Riverside, California 92521, United States
| | - Zili Wu
- Chemical
Sciences Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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18
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Keggin heteropolyacids supported on TiO 2 used in gas-solid (photo)catalytic propene hydration and in liquid-solid photocatalytic glycerol dehydration. Catal Today 2017. [DOI: 10.1016/j.cattod.2016.04.037] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Zhou W, Soultanidis N, Xu H, Wong MS, Neurock M, Kiely CJ, Wachs IE. Nature of Catalytically Active Sites in the Supported WO3/ZrO2 Solid Acid System: A Current Perspective. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03697] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wu Zhou
- School
of Physical Sciences, CAS Key Laboratory of Vacuum Sciences, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
- Department
of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Nikolaos Soultanidis
- Department of Chemical & Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Hui Xu
- Department
of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Michael S. Wong
- Department of Chemical & Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Matthew Neurock
- Department
of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Christopher J. Kiely
- Department
of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
- Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Israel E. Wachs
- Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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20
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ZrO2 nano particle catalyzed multi-component synthesis of 3-benzylidene-1-phenylquinoline-2,4(1H,3H)-diones and its antimicrobial activity. RESEARCH ON CHEMICAL INTERMEDIATES 2017. [DOI: 10.1007/s11164-017-2894-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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21
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Schnee J, Gaigneaux EM. Raman monitoring of a catalytic system at work: Influence of the reactant on the sensitivity to laser-induced heating. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 173:151-159. [PMID: 27632798 DOI: 10.1016/j.saa.2016.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/27/2016] [Accepted: 09/06/2016] [Indexed: 06/06/2023]
Abstract
Characterizing catalysts under working conditions is crucial to understand and to optimize their behavior and performance. However, when Raman spectroscopy is used, attention has to be paid to laser-induced artefacts. While laser irradiation is often claimed to lead to a temperature gradient between the integral catalyst bed and the sampling point, neither the circumstances when such effect appears, nor if it systematically occurs or not, are really explored in details. The present paper shows that the sensitivity of a catalyst to laser-induced heating largely depends on the gas composition under which the analysis is done, in particular that it depends whether the catalyst has adsorbed reactant molecules or not. These aspects are here addressed via the Raman in situ exploration of H3PW12O40. This heteropolyacid is a widely used acid catalyst due to its very high Brönsted acidity, approaching the superacid region. In particular, we have investigated the impact of laser irradiation in the Raman monitoring of solid H3PW12O40 at work under a flow of methanol in nitrogen at 50°C. When 1 single spectrum of H3PW12O40 was measured after 3h of exposure to methanol, the characteristic CH vibration bands of adsorbed methanol appeared. However, when spectra were measured continuously throughout the experiment, the same CH vibration bands were observed only during the first hour, then they disappeared and the characteristic bands of polyaromatic molecules appeared. Under continuous laser irradiation, adsorbed methanol was thus converted into polyaromatic coke as resulting from a laser-induced heating. However, the spectra collected under pure nitrogen show that the laser does not heat the catalyst in the absence of methanol. UV-Vis revealed the reason of the laser-induced heating in the presence of methanol, and the subsequent formation of coke. Actually the catalyst gets reduced by the adsorbed methanol, what darkens the catalyst bed. Such a darkening renders the catalyst sensitive to laser-induced heating, which in turn leads to the formation of coke. Under continuous laser irradiation, methanol thus auto-initiated its own catalytic conversion, finally leading to the deposition of coke. Such artefact must be avoided if one wants to study the true behavior of the catalyst at work. This paper shows that, for reducible samples analyzed in the presence of reductive molecules, this is only possible by shining the laser intermittently and not continuously. More generally, it actually shows that the adequate way to irradiate a catalyst (continuous vs intermittent) in an in situ/operando Raman analysis depends on the gas flow composition.
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Affiliation(s)
- Josefine Schnee
- Institute of Condensed Matter and Nanosciences (IMCN), MOlecules Solids and reactiviTy (MOST), Université catholique de Louvain (UCL), Place Louis Pasteur 1, L4.01.09, B-1348 Louvain-la-Neuve, Belgium
| | - Eric M Gaigneaux
- Institute of Condensed Matter and Nanosciences (IMCN), MOlecules Solids and reactiviTy (MOST), Université catholique de Louvain (UCL), Place Louis Pasteur 1, L4.01.09, B-1348 Louvain-la-Neuve, Belgium.
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22
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Ma J, Zhu C, Xu Y, Lu J, Huang L, Yang Z. Photocatalytic degradation of gaseous benzene with H3PW12O40/TiO2/palygorskite composite catalyst. JOURNAL OF SAUDI CHEMICAL SOCIETY 2017. [DOI: 10.1016/j.jscs.2015.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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23
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Aminophosphine Palladium(0) Complex Supported on ZrO2 Nanoparticles (ZrO2@AEPH2-PPh2-Pd(0)) as an Efficient Heterogeneous Catalyst for Suzuki–Miyaura and Heck–Mizoroki Reactions in Green Media. Catal Letters 2016. [DOI: 10.1007/s10562-016-1944-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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24
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Stolzenburg P, Freytag A, Bigall NC, Garnweitner G. Fractal growth of ZrO2nanoparticles induced by synthesis conditions. CrystEngComm 2016. [DOI: 10.1039/c6ce01916a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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25
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Tang S, Wu W, Fu Z, Zou S, Liu Y, Zhao H, Kirk SR, Yin D. Vanadium-Substituted Tungstophosphoric Acids as Efficient Catalysts for Visible-Light-Driven Oxygenation of Cyclohexane by Dioxygen. ChemCatChem 2015. [DOI: 10.1002/cctc.201500314] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Ladera RM, Ojeda M, Fierro JLG, Rojas S. TiO2-supported heteropoly acid catalysts for dehydration of methanol to dimethyl ether: relevance of dispersion and support interaction. Catal Sci Technol 2015. [DOI: 10.1039/c4cy00998c] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
TiO2-supported heteropoly acids are very active catalysts for DME production from methanol. Due to the interaction with the support, the most active catalysts are obtained when a monolayer of HPA is deposited on the support.
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Affiliation(s)
- Rosa María Ladera
- Grupo de Energía y Química Sostenibles
- Instituto de Catálisis y Petroleoquímica
- CSIC
- Madrid
- Spain
| | - Manuel Ojeda
- Grupo de Energía y Química Sostenibles
- Instituto de Catálisis y Petroleoquímica
- CSIC
- Madrid
- Spain
| | - José Luis G. Fierro
- Grupo de Energía y Química Sostenibles
- Instituto de Catálisis y Petroleoquímica
- CSIC
- Madrid
- Spain
| | - Sergio Rojas
- Grupo de Energía y Química Sostenibles
- Instituto de Catálisis y Petroleoquímica
- CSIC
- Madrid
- Spain
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27
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Qiu J, Zhou X, Mo Q, Liu F, Jiang L. Electrostatic assembled of Keggin-type polyoxometalates onto poly(4-vinylpyridine)-grafted poly(vinylidene fluoride) membranes. RSC Adv 2014. [DOI: 10.1039/c4ra07978g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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28
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Deng W, Zhu E, Liu M, Zhang Q, Wang Y. Cs-substituted tungstophosphate-supported ruthenium nanoparticles as efficient and robust bifunctional catalysts for the conversion of inulin and cellulose into hexitols in water in the presence of H2. RSC Adv 2014. [DOI: 10.1039/c4ra05939e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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29
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Bonfim RDPF, de Moura LC, Eon JG, Mentré O, Vezin H, Caldarelli S. Keggin (K5, H3O)[SiV3W9O40H]·xH2O: Characterization and crystal structure. J SOLID STATE CHEM 2014. [DOI: 10.1016/j.jssc.2014.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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30
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Role of vanadium in Keggin heteropoly molybdate supported on titania catalysts for oxidation reactions. J CHEM SCI 2014. [DOI: 10.1007/s12039-014-0575-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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31
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Ladera RM, Fierro JLG, Ojeda M, Rojas S. TiO2-supported heteropoly acids for low-temperature synthesis of dimethyl ether from methanol. J Catal 2014. [DOI: 10.1016/j.jcat.2014.01.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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32
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Guo W, Luo Z, Lv H, Hill CL. Aerobic Oxidation of Formaldehyde Catalyzed by Polyvanadotungstates. ACS Catal 2014. [DOI: 10.1021/cs5000763] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Weiwei Guo
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Zhen Luo
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Hongjin Lv
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Craig L. Hill
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
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33
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Study of acid–base properties of supported heteropoly acids in the reactions of secondary alcohols dehydration. Catal Today 2014. [DOI: 10.1016/j.cattod.2013.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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34
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Jafarpour M, Rezapour E, Ghahramaninezhad M, Rezaeifard A. A novel protocol for selective synthesis of monoclinic zirconia nanoparticles as a heterogeneous catalyst for condensation of 1,2-diamines with 1,2-dicarbonyl compounds. NEW J CHEM 2014. [DOI: 10.1039/c3nj00655g] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Feyzi M, Norouzi L, Rafiee HR. Kinetic study on the Cs(x)H(₃-x)PW₁₂O₄₀/Fe-SiO₂ nanocatalyst for biodiesel production. ScientificWorldJournal 2013; 2013:612712. [PMID: 24391465 PMCID: PMC3874311 DOI: 10.1155/2013/612712] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/20/2013] [Indexed: 11/18/2022] Open
Abstract
The kinetic of the transesterification reaction over the Cs(x)H(₃-x)PW₁₂O₄₀/Fe-SiO₂ catalyst prepared using sol-gel and impregnation procedures was investigated in different operational conditions. Experimental conditions were varied as follows: reaction temperature 323-333 K, methanol/oil molar ratio = 12/1, and the reaction time 0-240 min. The H₃PW₁₂O₄₀ heteropolyacid has recently attracted significant attention due to its potential for application in the production of biodiesel, in either homogeneous or heterogeneous catalytic conditions. Although fatty acids esterification reaction has been known for some time, data is still scarce regarding kinetic and thermodynamic parameters, especially when catalyzed by nonconventional compounds such as H₃PW₁₂O₄₀. Herein, a kinetic study utilizing Gc-Mas in situ allows for evaluating the effects of operation conditions on reaction rate and determining the activation energy along with thermodynamic constants including ΔG, ΔS, and ΔH. It indicated that the Cs(x)H(₃-x)PW₁₂O₄₀/Fe-SiO₂ magnetic nanocatalyst can be easily recycled with a little loss by magnetic field and can maintain higher catalytic activity and higher recovery even after being used 5 times. Characterization of catalyst was carried out by using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), N₂ adsorption-desorption measurements methods, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC).
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Affiliation(s)
- Mostafa Feyzi
- Faculty of Chemistry, Razi University, P.O. Box 6714967346, Kermanshah, Iran
- Nanoscience & Nanotechnology Research Center (NNRC), Razi University, P.O. Box 6714967346, Kermanshah, Iran
| | - Leila Norouzi
- Faculty of Chemistry, Razi University, P.O. Box 6714967346, Kermanshah, Iran
| | - Hamid Reza Rafiee
- Faculty of Chemistry, Razi University, P.O. Box 6714967346, Kermanshah, Iran
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36
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Chen G, Zhou Y, Zhao P, Long Z, Wang J. Mesostructured Dihydroxy-Functionalized Guanidinium-Based Polyoxometalate with Enhanced Heterogeneous Catalytic Activity in Epoxidation. Chempluschem 2013. [DOI: 10.1002/cplu.201300105] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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37
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Choi J, Kang D, Lee KH, Lee B, Kim KJ, Hur NH. Evidence for light-induced oxygen exchange in the oxidation of liquid hydrocarbons on oxygen 18-labelled titanium dioxide. RSC Adv 2013. [DOI: 10.1039/c3ra40460a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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38
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Efremenko I, Neumann R. Computational insight into the initial steps of the Mars-van Krevelen mechanism: electron transfer and surface defects in the reduction of polyoxometalates. J Am Chem Soc 2012; 134:20669-80. [PMID: 23210519 DOI: 10.1021/ja308625q] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metal oxides as a rule oxidize and oxygenate substrates via the Mars-van Krevelen mechanism. A well-defined α-Keggin polyoxometalate, H(5)PV(2)Mo(10)O(40), can be viewed as an analogue of discrete structure that reacts via the Mars-van Krevelen mechanism both in solution and in the gas phase. Guided by previous experimental observations, we have studied the key intermediates on the reaction pathways of its reduction by various compounds using high-level DFT calculations. These redox reactions of polyoxometalates require protons, and thus such complexes were explicitly considered. First, the energetics of outer-sphere proton and electron transfer as well as coupled proton and electron transfer were calculated for seven substrates. This was followed by identification of possible key intermediates on the subsequent reaction pathways that feature displacement of the metal atom from the Keggin structure and coordinatively unsaturated sites on the H(5)PV(2)Mo(10)O(40) surface. Such metal defects are favored at vanadium sites. For strong reducing agents the initial outer-sphere electron transfer, alone or possibly coupled with proton transfer, facilitates formation of metal defects. Subsequent coordination allows for formation of reactive ensembles on the catalyst surface, for which the selective oxygen-transfer step becomes feasible. Weak reducing agents do not facilitate defect formation by outer-sphere electron and/or proton transfers, and thus formation of metal defect structures prior to the substrate activation is suggested as an initial step. Calculated geometries and energies of metal defect structures support experimentally observed intermediates and demonstrate the complex nature of the Mars-van Krevelen mechanism.
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Affiliation(s)
- Irena Efremenko
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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39
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Wang CL, Zhang ZB, Fu J, Xu Y, Zhu DR. A New “Fully Reduced” Polyoxovanadate Constructed from Nanosized Triangle-Shaped [VIII3VIV18P6O60(DACH)3]}9−Cluster Anions Exhibiting Ferrimagnetic Interactions. Chemistry 2012; 18:11909-12. [DOI: 10.1002/chem.201200261] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Indexed: 11/07/2022]
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40
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Srilatha K, Sree R, Prabhavathi Devi BLA, Sai Prasad PS, Prasad RBN, Lingaiah N. Preparation of biodiesel from rice bran fatty acids catalyzed by heterogeneous cesium-exchanged 12-tungstophosphoric acids. BIORESOURCE TECHNOLOGY 2012; 116:53-57. [PMID: 22609655 DOI: 10.1016/j.biortech.2012.04.047] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 04/11/2012] [Accepted: 04/12/2012] [Indexed: 06/01/2023]
Abstract
Biodiesel synthesis from rice bran fatty acids (RBFA) was carried out using cesium exchanged 12-tungstophosphoric acid (TPA) catalysts. The physico-chemical properties of the catalysts were derived from X-ray diffraction (XRD), Fourier transform infrared (FTIR), temperature programmed desorption (TPD) of NH(3) and scanning electron microscopy (SEM). The characterization techniques revealed that the Keggin structure of TPA remained intact as Cs replaced protons. The partial exchange of Cs for protons resulted in an increase in acidity and the catalysts with one Cs(+) (Cs(1)H(2)PW(12)O(40)) showed highest acidity. Under optimized conditions about 92% conversion of RBFA was obtained. The catalyst was reused for five times and retained of its original activity. Pseudo-first order model was applied to correlate the experimental kinetic data. Modified tungstophosphoric acids are efficient solid acid catalysts for the synthesis of biodiesel from the oils containing high FFA.
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Affiliation(s)
- K Srilatha
- Catalysis Laboratory, Inorganic & Physical Chemistry Division, Hyderabad 500607, India
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41
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Aparicio-Anglès X, Miró P, Clotet A, Bo C, Poblet JM. Polyoxometalates adsorbed on metallic surfaces: immediate reduction of [SiW12O40]4− on Ag(100). Chem Sci 2012. [DOI: 10.1039/c2sc20210g] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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42
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Fu J, Sun H, Xu Y, Wang C, Zhu D, Sun Q, Liu H. [Ni(C17H20N4)4][H5PMoVI8VIV4O40(VIVO)2]·8H2O: confinement of heteropoly anions in Ni-containing rigid concave surfaces with high catalytic activity in the oxidation of styrene. CrystEngComm 2012. [DOI: 10.1039/c2ce25419k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Four novel polytungstate compounds built up of paradodecatungstate clusters and transition-metal complexes/transition metal: Synthesis, structure, and electrochemical properties. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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44
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Rao PSN, Srihari Kumar A, Sai Prasad PS, Lingaiah N. Surface, structural and catalytic properties of heteropolymolybdate supported on vanadia dispersed alumina catalysts. REACTION KINETICS MECHANISMS AND CATALYSIS 2011. [DOI: 10.1007/s11144-011-0388-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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45
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Molinari JE, Nakka L, Kim T, Wachs IE. Dynamic Surface Structures and Reactivity of Vanadium-Containing Molybdophosphoric Acid (H3+xPMo12–xVxO40) Keggin Catalysts during Methanol Oxidation and Dehydration. ACS Catal 2011. [DOI: 10.1021/cs2001362] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Julie E. Molinari
- Operando Molecular Spectroscopy and Catalysis Laboratory, Chemical Engineering Department, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Lingaiah Nakka
- Operando Molecular Spectroscopy and Catalysis Laboratory, Chemical Engineering Department, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Taejin Kim
- Operando Molecular Spectroscopy and Catalysis Laboratory, Chemical Engineering Department, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Israel E. Wachs
- Operando Molecular Spectroscopy and Catalysis Laboratory, Chemical Engineering Department, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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46
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Zhou C, Ma Z, Ren Z, Mao X, Dai D, Yang X. Effect of defects on photocatalytic dissociation of methanol on TiO2(110). Chem Sci 2011. [DOI: 10.1039/c1sc00249j] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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47
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The role of vanadium in ammonium salt of heteropoly molybdate supported on niobia for selective oxidation of benzyl alcohol. CATAL COMMUN 2010. [DOI: 10.1016/j.catcom.2009.12.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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48
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Wachs IE, Roberts CA. Monitoring surface metal oxide catalytic active sites with Raman spectroscopy. Chem Soc Rev 2010; 39:5002-17. [DOI: 10.1039/c0cs00145g] [Citation(s) in RCA: 233] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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