Article
Chemistry, Multidisciplinary
Janis Musso, Jordan De Jesus Silva, Mathis J. Benedikter, Jonas Groos, Wolfgang Frey, Christophe Coperet, Michael R. Buchmeiser
Summary: Recent studies have shown that cationic d(0) group 6 olefin metathesis catalysts exhibit higher activity compared to their neutral counterparts, and their catalytic performance is greatly enhanced by immobilization on silica.
Article
Chemistry, Physical
Bin Zhang, Israel E. Wachs
Summary: A series of supported ReOx catalysts were investigated to identify the unique surface anchoring sites on oxide supports responsible for activating the surface ReO4 sites for propylene metathesis. The specific oxide support was found to control the number of activated sites and propylene metathesis activity, revealing that the oxide support is a potent ligand for the surface ReOx sites.
Article
Engineering, Environmental
Zhuo Yang, Zhongpeng Wang, Wei Liu, Ben Wang, Xinru Luan, Yujia Zhai, Liguo Wang
Summary: A series of MnOx supported on MgAl2O4 spinel catalysts were prepared for low temperature SCR of NOx with ammonia. The Mn0.12/MAS-700 catalyst showed the best denitrification performance, with more than 80% conversion of NO at 150-300 degrees C and higher than 60% N2 selectivity. The addition of Mn species increased the surface acidity of weak acid centers which promoted the catalyst activity.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Physical
Pratya Promchana, Kittisak Choojun, Wanwisa Limphirat, Yingyot Poo-arporn, Tawan Sooknoi
Summary: Acetylene in ethylene-rich feed can be removed via acetylene/ethylene cross-metathesis over WO3-supported catalysts at 450 degrees C, yielding 1,3-butadiene with cyclohexene as a minor product. The catalyst must be treated with ethylene at 600 degrees C to generate a genuinely active site of tungsten (IV) alkylidene species (W=CH2). The H2 treatment decreases surface W--O concentration, and hence the activity.
APPLIED CATALYSIS A-GENERAL
(2023)
Article
Chemistry, Physical
Bin Zhang, Shuting Xiang, Anatoly Frenkel, Israel E. Wachs
Summary: The study investigates the increased activity of MoOx catalysts by surface modification and finds that specific anchoring surface hydroxyls control the number of active sites and the reaction rate of propylene metathesis, while the surface acid nature does not directly affect the number of active sites.
Article
Chemistry, Multidisciplinary
Jessica Rodriguez, Maxime Boudjelel, Leonard J. Mueller, Richard R. Schrock, Matthew P. Conley
Summary: This passage describes the reaction of W(NAr) ((C4H8)-C-13) (OSiPh3)(2) (1) with partially dehydroxylated silica at 700 degrees C. The results show that the reaction outcome is highly influenced by the reaction conditions. Different compounds are formed as products, and their formation is affected by light and heating treatment.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Andy Y. Yang, Matt Law
Summary: Freeze-drying aqueous slurries of gold NCs with various powdered supports produces highly uniform, well-dispersed supported NCs without the need for high-temperature calcination. This slurry freeze-drying method offers superior product uniformity, reproducibility, and scalability for making supported NC catalysts.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Ki-Young Yoon, Jinkyung Noh, Quan Gan, Julian P. Edwards, Robert Tuba, Tae-Lim Choi, Robert H. Grubbs
Summary: The study presents a continuous circular process for the scalable synthesis of pure cyclic polymers. This process utilizes silica-supported ruthenium catalysts and newly designed glassware to enable polymerization, polymer separation, and catalyst recovery in situ. The process minimizes manual labor, maximizes catalyst security, and guarantees the purity of cyclic polymers.
Article
Chemistry, Physical
Simi Li, Yan Huang, Lingkui Zhao, Junfeng Zhang
Summary: This study presents a synthetic protocol for the preparation of oxygen-functionalized activated carbon supported vanadium catalysts. The catalysts exhibit enhanced acid and redox properties, leading to improved catalytic activity for low-temperature selective catalytic reduction. In-situ experiments reveal multiple adsorption and reaction mechanisms on the catalyst surface, which are significant for the understanding of the catalytic process.
SURFACES AND INTERFACES
(2022)
Article
Chemistry, Physical
Bin Zhang, Soe Lwin, Shuting Xiang, Anatoly Frenkel, Israel E. Wachs
Summary: The activity of catalysts supported by surface ReOx is controlled by the number and type of ligands on the oxide support, while the overall activity is influenced by the number of activated sites.
Article
Chemistry, Physical
Bingyu Lin, Biyun Fang, Yuyuan Wu, Chunyan Li, Jun Ni, Xiuyun Wang, Jianxin Lin, Chak-tong Au, Lilong Jiang
Summary: Metal-support interactions strongly impact the catalytic performances of ceria-supported metal catalysts, and hydrogen treatment at high temperature is essential for the preparation of catalysts with strong metal-support interaction (SMSI). CO activation of a Ru/CeO2 catalyst enhances the reduction degree and exposure of Ru species, leading to the formation of electron-enriched Ru delta- species and Ru delta-OV-Ce3+ sites, resulting in high ammonia synthesis activity and alleviating the ill effect of hydrogen poisoning. These findings are crucial for designing supported metal catalysts with metallic species as active sites.
Article
Materials Science, Ceramics
Chunmei Wang, Haohao Zhang, Huakang Zhang, Yifei Wang, Lirong Yang, Zhigang Liu, Xiaoxin Feng
Summary: MnOx-supported geopolymer pellets catalysts with 10 wt.% MnOX were prepared by hydrothermal impregnation and tested for low-temperature NH3-SCR deNO(x) performance. The catalyst synthesized at 120℃ exhibited the highest activity, with NOx conversion rates of approximately 90% at 120℃ and 98% at 280℃. It also showed more than 85% N-2 selectivity in the temperature range of 120-200℃, attributed to better dispersion of MnOx, multivalent oxidation state of manganese, higher content of surface chemisorbed oxygen, and more acid sites.
INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Thotsatham Takkawatakarn, Supareak Praserthdam, Sippakorn Wannakao, Joongjai Panpranot, Piyasan Praserthdam
Summary: The study found that the addition of MgO affected the generation of new species of coke deposited on WO3/SiO2 and MgO itself, and the difference in reaction temperature (300 vs. 450 degrees C) led to different types and temperatures of coke formation, indicating a significant impact of temperature changes on reaction pathways and outcomes.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Bingqiao Xie, Tze Hao Tan, Kourosh Kalantar-Zadeh, Jiewei Zheng, Priyank Kumar, Junjie Jiang, Shujie Zhou, Jason Scott, Rose Amal
Summary: In this research, a ceria-modified Cu/ZnO/Al2O3 catalyst was developed for efficient methanol production at a lower temperature under light illumination. The influence of ceria loading on the morphological and surface chemistry characteristics of the catalyst was systematically assessed. The addition of ceria promoted CO2 chemisorption and favored methanol production, while excessive ceria loading decreased the preference for methanol.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Multidisciplinary
Defa Gu, Guangwen Li, Yushan Liu, Yuzhou Liu
Summary: The formation of hierarchical bonds through olefin metathesis can improve the stability of covalent organic frameworks while maintaining their versatility.
Article
Chemistry, Organic
Yohei Ueda, Hayato Tsurugi, Kazushi Mashima
Summary: Cobalt-catalyzed hydroalkynylation of alkynes, alkenes, and imines allows for the synthesis of internal alkynes with various functional groups adjacent to the carbon-carbon triple bond in an atom-economical manner. In addition, cross-coupling reactions using alkynylcobalt species generated in situ from terminal alkynes, haloalkynes, and metal acetylides selectively provide internal aryl and alkylalkynes.
Article
Chemistry, Multidisciplinary
Anna Giorgia Nobile, David Trummer, Zachariah J. Berkson, Michael Worle, Christophe Coperet, Pierre-Adrien Payard
Summary: The structure of the surface sites of the Union Carbide ethylene polymerization catalyst remains elusive, but recent research suggests the presence of monomeric and dimeric Cr(ii) sites, as well as Cr(iii) hydride sites. However, the analysis of their structure is complicated by large paramagnetic H-1 shifts induced by unpaired electrons on the Cr atoms. In this study, a cost-efficient DFT methodology was implemented to calculate the H-1 chemical shifts for antiferromagnetically coupled metal dimeric sites, allowing for the assignment of observed H-1 shifts for the industrial-like UC catalyst and confirming the presence of monomeric and dimeric Cr(ii) sites as well as dimeric Cr(iii)-hydride sites.
Article
Chemistry, Physical
Kosuke Higashida, Valentin Smail, Haruki Nagae, Jean-Francois Carpentier, Kazushi Mashima
Summary: We successfully achieved nickel(0)-catalyzed asymmetric allylic alkylation (AAA) of beta-dicarbonyl compounds under ambient conditions by activating unstrained C-C bonds of 2-allylated 2-methylcyclohexane-1,3-dione derivatives. The reaction produced quaternary chiral compounds with high yield and enantioselectivity. The mechanism of the AAA reaction with the Ni(0)-(S)-tol-MeO-BIPHEP catalyst system was elucidated through control experiments and DFT calculations.
Article
Chemistry, Multidisciplinary
Maximilian Krodel, Lorenz Abduly, Manouchehr Nadjafi, Agnieszka Kierzkowska, Alexander Yakimov, Alexander H. Bork, Felix Donat, Christophe Coperet, Paula M. Abdala, Christoph R. Mueller
Summary: Understanding the effects of different structural parameters of CaO-based CO2 sorbents on cyclic CO2 uptake is crucial for their advancement. Through mechanochemical activation, CaO-based sorbents with varying ratios of Na2CO3:CaCO3 were synthesized to investigate the impact of sodium species on the sorbents' structure, morphology, carbonation rate, and cyclic CO2 uptake. The addition of Na2CO3 in the range of 0.1-0.2 mol% significantly improved CO2 uptake by up to 80% after 10 cycles compared to untreated CaCO3, while higher Na2CO3 loadings (>0.3 mol%) led to a decrease of more than 40% in cyclic CO2 uptake due to accelerated deactivation caused by sintering and the presence of crystalline Na2Ca(CO3)(2) species with high mobility of Na.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Editorial Material
Chemistry, Multidisciplinary
Thomas R. Ward, Christophe Coperet
Article
Chemistry, Physical
Kohei Nishi, Hayato Tsurugi, Kazushi Mashima
Summary: Chromium(III) trichloride combined with aryl/alkyl Grignard reagents showed high catalytic activity for the synthesis of syn-2-aryl/alkyl-1,2-dihydronaphthalen-1-ols through the ring-opening aryl/alkylation of 7-oxabenzonorbornadiene derivatives. The chromium catalyst allowed the use of unstable aryl Grignard reagents with esters and N-protecting groups. In situ formed diarylchromate(I) from tetraarylchromate(III) was identified as the active species in this catalytic reaction based on control experiments.
Article
Chemistry, Multidisciplinary
Weicheng Cao, Alexander Yakimov, Xudong Qian, Jiongzhao Li, Xiaogang Peng, Xueqian Kong, Christophe Coperet
Summary: A strategy based on detecting NMR signatures of 113Cd, 77Se, and 15N augmented with DFT modeling was developed to investigate the interaction between amine ligands and CdSe nanocrystals (NCs). The results showed that amine ligands not only directly bond to surface sites, but also interact through hydrogen bonding with absorbed water. This study provides molecular-level insight into the surface properties of amine-capped CdSe NCs and lays the foundation for designing colloidal NCs with tailored properties.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Daniel F. Abbott, Yuan-Zi Xu, Denis A. Kuznetsov, Priyank Kumar, Christoph R. Mueller, Alexey Fedorov, Victor Mougel
Summary: In this study, the catalytic activity of a Fe-substituted two-dimensional molybdenum carbide in nitrate reduction reaction (NO3RR) was investigated. The results showed that the catalyst exhibited high efficiency in both acidic and neutral media. The formation of surface oxygen vacancies promoted by Fe sites was identified as the active sites for NO3RR, similar to the mechanism of natural Mo-based nitrate reductase enzymes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Seraphine B. X. Y. Zhang, Quentin Pessemesse, Zachariah J. Berkson, Alexander P. Van Bavel, Andrew D. Horton, Pierre-Adrien Payard, Christophe Coperet
Summary: Li/MgO is a prototypical material for oxidative coupling of methane (OCM) with high C-2 selectivity. This study demonstrates that Li/MgO is also an effective catalyst for non-oxidative coupling of methane (NOCM). The presence of Li favors the formation of magnesium acetylide (MgC2), which promotes C-C bond formation and enhances C-2 selectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Zixuan Chen, Nora K. Zimmerli, Muhammad Zubair, Alexander V. Yakimov, Snaedis Bjorgvinsdottir, Nicholas Alaniva, Elena Willinger, Alexander B. Barnes, Nicholas M. Bedford, Christophe Coperet, Pierre Florian, Paula M. Abdala, Alexey Fedorov, Christoph R. Mueller
Summary: Gallia-based shells with varying thickness were prepared using atomic layer deposition (ALD) and their atomic-scale structure was studied. The abundance and strength of Lewis acid sites and Bronsted acid sites in the shells were found to correlate with the catalytic performance. This provides insights for the rational design of active Ga-based catalysts.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Hui Zhou, Scott R. Docherty, Nat Phongprueksathat, Zixuan Chen, Andrey V. Bukhtiyarov, Igor P. Prosvirin, Olga V. Safonova, Atsushi Urakawa, Christophe Coperet, Christoph R. Muller, Alexey Fedorov
Summary: A Cu-Zn/SiO2 catalyst was developed for the efficient and selective hydrogenation of CO2 to methanol. The optimized catalyst exhibited an intrinsic methanol formation rate of 4.3 g h(-1) g(Cu) (-1) and a selectivity to methanol of 83% at 230 degrees C and 25 bar.
Article
Chemistry, Multidisciplinary
Lukas Rochlitz, Jorg W. A. Fischer, Quentin Pessemesse, Adam H. Clark, Anton Ashuiev, Daniel Klose, Pierre-Adrien Payard, Gunnar Jeschke, Christophe Coperet
Summary: This study investigates the effect of Ti doping on the catalytic performance of Pt and PtZn materials in propane dehydrogenation. The results show that Ti-doping significantly changes the electronic structure of nanoparticles and improves the stability of the materials.
Article
Chemistry, Multidisciplinary
Christian Ehinger, Xiaoyu Zhou, Max Candrian, Scott R. Docherty, Stephan Pollitt, Christophe Coperet
Summary: The synthesis of well-defined materials as model systems for catalysis and related fields plays a crucial role in understanding catalytic processes at a molecular level. Organometallic precursors have been developed to produce monodispersed supported nanoparticles, nanocrystals, and films. A new family of precursors based on group 10 metals has been discovered, which can generate small and monodispersed nanoparticles on metal oxides. These precursors show potential for synthesizing bimetallic catalyst materials and have been demonstrated for hydrogenation of CO2 to methanol.
Article
Chemistry, Multidisciplinary
Haruki Nagae, Saki Matsushiro, Jun Okuda, Kazushi Mashima
Summary: We discovered that a cationic hetero tetranuclear complex with a calcium and three cobalt ions demonstrated high catalytic activity for the alternating copolymerization of propylene oxide (PO) and carbon dioxide (CO2). The tertiary anilinium salt [PhNMe2H][B(C6F5)(4)] was identified as the best additive to generate the cationic species and maintain polymer selectivity and carbonate linkage, even at 1.0 MPa CO2. Density functional theory calculations revealed that the reaction pathway mediated by the cationic complex is more favorable than that mediated by the neutral complex, with an energy difference of 1.0 kcal mol(-1). Additionally, we found that the exchange of flexible ligands between calcium and cobalt ions is crucial for the smooth proceeding of the alternating copolymerization.
Article
Chemistry, Multidisciplinary
Xiaoyu Zhou, Gregory A. Price, Glenn J. Sunley, Christophe Coperet
Summary: This study synthesized cobalt nanoparticles with different sizes through surface organometallic chemistry and found that under CO2 hydrogenation conditions, smaller particles mainly catalyzed the reverse water-gas shift reaction, while larger particles were more favorable for methanation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)