Article
Chemistry, Multidisciplinary
Jeffery L. White, Kuizhi Chen, Anya Zornes, Vy Nguyen, Bin Wang, Zhehong Gan, Steven P. Crossley
Summary: This study reveals the presence of at least two types of paired active sites in zeolite catalysts through NMR experiments, and finds that these paired sites play a crucial role in reactivity. Additionally, it is observed that synthetic and postsynthetic modifications affect the quantity and arrangement of these paired sites.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Engineering, Chemical
Shusei Tanizume, Sota Maehara, Katsunori Ishii, Takamasa Onoki, Takuya Okuno, Hiromasa Tawarayama, Shinji Ishikawa, Mikihiro Nomura
Summary: By synthesizing a defect-free MFI zeolite membrane on a porous silica substrate, high selectivity and yield of olefins from methanol conversion can be achieved.
SEPARATION AND PURIFICATION TECHNOLOGY
(2021)
Article
Chemistry, Physical
Zhe Feng, Xin Liu, Changgong Meng
Summary: By using first-principles calculations, we investigated the electronic structures of Ga species and their interconversion pathways in zeolite channels. Thermodynamics calculations revealed that [Ga]+(I) is plausible at high temperature and low PH2O, while [Ga(OH)2]+(III) is plausible at low temperature and high PH2O. The coordination of Ga centers with -H and O-containing ligands affects the dissociation of H2 and the formation of H2O, with high energy barriers observed. These findings provide insights into the formation and evolution of atomically dispersed reaction centers in zeolite channels under operation conditions.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Amy J. Knorpp, Ana B. Pinar, Christian Baerlocher, Lynne B. McCusker, Nicola Casati, Mark A. Newton, Stefano Checchia, Jordan Meyet, Dennis Palagin, Jeroen A. van Bokhoven
Summary: The research investigates the conversion of methane to methanol using copper-exchanged zeolites, with current productivity levels still too low. By understanding the nature of the active site, more effective catalysts could be designed for this conversion process.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Green & Sustainable Science & Technology
Jorge G. Huerta-Munoz, Maria De Lourdes Guzman-Castillo, Hector Armendariz-Herrera, Jaime S. Valente, Antonio Aragon-Pina, Maria-Guadalupe Cardenas-Galindo, Brent E. Handy
Summary: The synthesis of highly crystalline ZSM-5 zeolite using recycled aluminum and silicon wastes was investigated. The study examined the effects of impurities from the wastes on crystallinity, particle morphology, surface area, and porosity. The use of glycerol as an alternative to mineral base solutions and the hydrothermal treatment resulted in the formation of hierarchical ZSM-5 zeolite. The upcycling of scrap aluminum and municipal glass to catalytic-grade ZSM-5 has the potential to compete with existing processes and has positive social and environmental impacts.
CLEAN-SOIL AIR WATER
(2022)
Article
Engineering, Chemical
Jiancheng Lan, Linzhe Li, Wensen Song, Hammad Saulat, Haowen Wu, Jianhua Yang, Chengmin Yang, Yang Li, Jinming Lu, Yan Zhang
Summary: Pure-silica MFI zeolite membrane with ethanol-selectivity was successfully fabricated using TBA(+) and TEA(+) as templates and cooperating agents. This approach outperformed the use of single templates in achieving desired membrane properties.
Article
Chemistry, Physical
Bozhidar Grahovski, Ralitsa Velinova, Pavletta Shestakova, Anton Naydenov, Hristo Kolev, Iliyana Yordanova, Georgi Ivanov, Krasimir Tenchev, Silviya Todorova
Summary: ZSM-5 zeolites with different Si/Al ratios were modified using a buffer solution of HF and NH4F, resulting in a material with secondary mesoporosity. Deposition of cobalt from an aqueous solution of cobalt acetate on the surface of treated samples led to the formation of various cobalt oxide species, including bulk-like Co3O4 phases, Co2+ in ion exchange positions, and silicate-like phases. The catalysts prepared using the treated ZSM-5 exhibited higher activity in propane and n-hexane oxidation reactions compared to catalysts containing untreated zeolite. This improvement can be attributed to the finer dispersion of metal oxide particles and the presence of secondary mesoporosity, which provide access to a larger number of active sites.
Article
Chemistry, Multidisciplinary
Manoj Ravi, Vitaly L. Sushkevich, Jeroen A. van Bokhoven
Summary: The Lewis acidic aluminum in zeolites can be transformed into octahedrally coordinated aluminum, which serves as the precursor of Lewis acid sites. These Lewis acid sites preferentially locate in the pore structure of mordenite, particularly in the side-pockets. By reverting the octahedrally coordinated aluminum back to a tetrahedral geometry, the corresponding Bronsted acid sites are restored, showing a reversible switch between Lewis and Bronsted acidity.
Article
Chemistry, Physical
P. A. Georgiev, N. Drenchev, K. I. Hadjiivanov, J. Ollivier, T. Unruh, A. Albinati
Summary: The study reveals differences in the binding form, quantity, and stability of copper with dihydrogen in different ZSM-5 zeolites, influenced by the copper exchange level and aluminum distribution.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Applied
Xunming Su, Zhong-Pan Hu, Jingfeng Han, Yuhong Jia, Shutao Xu, Jin Zhang, Dong Fan, Yingxu Wei, Zhongmin Liu
Summary: An environment-friendly, stable, and efficient catalyst for propane dehydrogenation (PDH) is developed by embedding zinc gluconate into a pure silica MFI zeolite framework. The Zn-MFI zeolites exhibit excellent catalytic performance due to the formation of uniform tetrahedrally coordinated Zn sites, which promote C-H bond cleavage and weaken propylene adsorption. The promising utilization of Zn-MFI zeolites in industry is indicated by their excellent performance.
MICROPOROUS AND MESOPOROUS MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Tianyi Fu, He Ding, Jingshuang Zhang, Peng Bai, Jiafei Lyu, Xianghai Guo
Summary: Hierarchical aluminosilicate zeolites with uniform mesoporosity were successfully synthesized by one-stage crystallization under constant temperature using a novel single-head quaternary ammonium salt as mesoporogen and structure-directing agent. The zeolites exhibited outstanding catalytic activity with good reusability towards bulky aldol condensation.
JOURNAL OF MATERIALS SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Huan V. Doan, Ka Ming Leung, Valeska P. Ting, Asel Sartbaeva
Summary: This research systematically studied a series of six chabazite zeolites obtained through exchanging the parent chabazite with cations of different valences and atomic radii. It was found that the differences in valence and size between extra-framework cations significantly affect the abundance of these cations positioned in the framework, resulting in differing nitrogen sorption ability in the synthesised chabazite zeolites. These findings contribute to better understanding of how the zeolite counter-cation influences the ability of CHA material to selectively sequester and separate gases using the trapdoor mechanism.
Article
Energy & Fuels
Latifah Hauli, Dieni Mansur, Saepurahman, Aminuddin
Summary: Catalytic pyrolysis of palm fronds using zeolite extrudates with different topologies and SiO2/Al2O3 ratios was investigated. The presence of zeolite during pyrolysis led to a reduction in bio-oil yield and an increase in gas yield. The analysis revealed the presence of furan and aromatics in the bio-oil, which were absent in non-catalytic pyrolysis. Gas analysis showed an increase in CO and CO2 yield, indicating the promotion of decarbonylation and decarboxylation. MFI and BEA-1 zeolites were more effective for deoxygenation at a low catalyst-to-feed ratio.
BIOMASS CONVERSION AND BIOREFINERY
(2023)
Article
Chemistry, Multidisciplinary
Guangyue Xu, Xiang Zhang, Zhuoya Dong, Wanying Liang, Tianci Xiao, Huiyong Chen, Yanhang Ma, Yang Pan, Yao Fu
Summary: In this study, a ferric catalyst confined in a zeolite framework was synthesized, which exhibited high selectivity and stability, and showed resistance to coking.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Applied
Anna Rokicinska, Marek Drozdek, Elzbieta Bogdan, Adam Wegrzynowics, Piotr Michorczyk, Piotr Kustrowski
Summary: A facile method using 3D printing to fabricate ceramic monoliths for Co3O4-based catalysts of total oxidation of volatile organic compounds was developed. The monoliths, coated with a MFI zeolite layer, showed excellent catalytic activity in toluene combustion due to highly dispersed Co3O4 spinel particles. The stability tests confirmed the longevity and consistent performance of the monolith catalysts in prolonged reactions.
Article
Chemistry, Multidisciplinary
Shuhei Yasuda, Yusuke Kunitake, Ryota Osuga, Kengo Nakamura, Takeshi Matsumoto, Keita Sago, Junko N. Kondo, Mizuho Yabushita, Atsushi Muramatsu, Toshiyuki Yokoi
Summary: Supported nickel CHA-type zeolites with different framework compositions were synthesized and the effect of heteroatoms in the framework on the state of the introduced Ni species was investigated. The use of aluminosilicate-type framework led to the formation of highly dispersed and nano-sized Ni species, resulting in the highest catalytic performance in the oxidative conversion of CH4.
Article
Engineering, Chemical
Masato Sawada, Takeshi Matsumoto, Ryota Osuga, Shuhei Yasuda, Sungsik Park, Yong Wang, Junko N. Kondo, Hiroaki Onozuka, Susumu Tsutsuminai, Toshiyuki Yokoi
Summary: In this study, boroaluminosilicate zeolites with varying Si/Al ratios were synthesized using a direct crystallization method. The addition of CTAB in the synthesis gel led to the formation of smaller particles and larger external surface area in the resulting zeolites. These CTAB-containing zeolites showed enhanced catalyst lifetime and propylene selectivity in the methanol-to-olefin reaction. Spectroscopic analysis confirmed that CTAB had negligible impact on the local structure of the zeolites, but decreased the amount of Al and related acid sites on the external surface. This study revealed the dual role of CTAB in controlling particle size and Al site distribution, which contributed to the improved catalytic performance.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Chemistry, Physical
Hiroto Toyoda, Ryota Osuga, Yong Wang, Sungsik Park, Koji Yazawa, Hermann Gies, Christopher J. Gilbert, Bilge Yilmaz, C. P. Kelkar, Toshiyuki Yokoi
Summary: This study investigates the location and acidic properties of Brønsted acid sites derived from framework Al atoms in MSE-type zeolites through Al-27 MQMAS NMR and in situ IR techniques. It has been found that there is a significant difference in the location of acid sites between MCM-68 and UZM-35. The unique catalytic activities of these acid sites in hydrocarbon cracking reactions are attributed to the differences in their locations.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Energy & Fuels
Satit Yousatit, Ryota Osuga, Junko N. Kondo, Toshiyuki Yokoi, Chawalit Ngamcharussrivichai
Summary: In this study, a mesoporous carbon/silica (MCS) nanocomposite was synthesized as a catalyst support for the production of 5-hydroxymethylfurfural (HMF) from glucose. By modifying the MCS surface, a series of acid-base catalysts were developed, and the acid-base properties could be tuned by adjusting the content of sulfonic acid and amino propyl groups. The developed MCS-SO3H-NH2 catalyst showed high HMF yield and selectivity when compared to other catalyst systems.
Article
Energy & Fuels
Ryota Osuga, Ginpei Tanaka, Mizuho Yabushita, Kakeru Ninomiya, Sachiko Maki, Maiko Nishibori, Kiyoshi Kanie, Atsushi Muramatsu
Summary: Fe-substituted MWW-type zeolites were successfully synthesized using a mechanochemically assisted hydrothermal synthesis, which involved a mechanochemical reaction between SiO2 and a-FeOOH as the first step and a hydrothermal treatment for crystallization as the second step. The resulting zeolites had well-introduced and dispersed Fe species in their framework, showing improved homogeneity compared to samples prepared by the conventional hydrothermal method.
JOURNAL OF THE JAPAN PETROLEUM INSTITUTE
(2022)
Article
Engineering, Chemical
Ryota Osuga, Atsushi Neya, Motohiro Yoshida, Mizuho Yabushita, Shuhei Yasuda, Sachiko Maki, Kiyoshi Kanie, Toshiyuki Yokoi, Atsushi Muramatsu
Summary: This study successfully improved the catalytic performance of low-temperature oxidative coupling of methane by using Ce-MFI zeolite supported Pd catalysts modified by a second metal. It was found that the coexistence of Pd and Co on Ce-MFI positively affected the C2H6 yield, and the highly dispersed Ce species in Ce-MFI also played a positive role in the catalytic reaction.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Chemistry, Physical
Junko N. Kondo, Shuo Ge, Tomohiro Suzuki, Ryota Osuga, Takeshi Matsumoto, Toshiyuki Yokoi, Yugo Shimizu, Atsushi Fukazawa, Naoki Shida, Mahito Atobe
Summary: For the first time, on-top hydrogen on a Pd cathode (Pd-H) was observed using operando infrared spectroscopy, and it was found to be stabilized by co-adsorbed solvent molecules. The spectroscopic analysis also revealed changes in the solvent's spectra when Pd-H species were present.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Eisuke Yoda, Ryota Osuga
Summary: This study prepared organic-cation-exchanged mordenite ([bmim]-MOR) by performing the ion exchange of H+ on mordenite (MOR) with an organic cation, 1-butyl-3-methylimidazolium ([bmim](+)). H-2 adsorption on [bmim]-MOR was demonstrated to be dissociative through monitoring with FT-IR. The hydrogen molecules were observed to dissociate into H+ and H- and interact with different sites on [bmim]-MOR.
REACTION KINETICS MECHANISMS AND CATALYSIS
(2023)
Article
Chemistry, Physical
Meilin Tao, Satoshi Ishikawa, Takuji Ikeda, Shunsaku Yasumura, Kosuke Shimoda, Ryota Osuga, Yuan Jing, Takashi Toyao, Ken-ichi Shimizu, Hiromi Matsuhashi, Wataru Ueda
Summary: In this study, the crystal structure and acid properties of Zr3SO9 were investigated. It was found that Zr3SO9 exhibited excellent catalytic activity for acid reactions, surpassing typical acid catalysts. The introduction of H2O transformed the acid sites of Zr3SO9, resulting in a shift from Lewis to Bronsted acid sites.
Article
Chemistry, Physical
Mizuho Yabushita, Ryota Osuga, Toshiyuki Yokoi, Atsushi Muramatsu
Summary: Oxidative upgrading of methane into valuable products can be achieved at low temperatures over zeolite-based catalysts. The unique tunability provided by zeolite framework structures enables the design of active species, resulting in excellent catalytic performance. This article categorizes the active species in zeolite-based catalysts into three groups and provides a comprehensive overview of their performance, structure, and catalysis.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Kengo Nakamura, Peipei Xiao, Ryota Osuga, Yong Wang, Shuhei Yasuda, Takeshi Matsumoto, Junko N. Kondo, Mizuho Yabushita, Atsushi Muramatsu, Hermann Gies, Toshiyuki Yokoi
Summary: This research emphasized the importance of Al distribution in CHA-type zeolite for the formation of active Cu species and oxidative conversion of CH4. Isolated Al atoms in the zeolite framework were found to be beneficial for producing CH3OH. Acid sites also played a significant role in the production of hydrocarbons, converting CH3OH into hydrocarbons.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Peipei Xiao, Kengo Nakamura, Yao Lu, Jun Huang, Lizhuo Wang, Ryota Osuga, Maiko Nishibori, Yong Wang, Hermann Gies, Toshiyuki Yokoi
Summary: CH4 and N2O are important greenhouse gases. Converting them into valuable chemicals can help address the environmental and energy problems caused by increasing greenhouse gas emissions and the growing demand for chemicals. In this study, Fe-AEI zeolites with different Si/Fe ratios were successfully synthesized and used as catalysts for the direct oxidation of methane with N2O, exhibiting high catalytic activity due to the highly dispersed Fe species. A reaction pathway was proposed based on the results and spectra.
Article
Chemistry, Physical
Junko N. Kondo, Shuo Ge, Tomohiro Suzuki, Ryota Osuga, Takeshi Matsumoto, Toshiyuki Yokoi, Yugo Shimizu, Atsushi Fukazawa, Naoki Shida, Mahito Atobe
Summary: Pd-H species stabilized by co-adsorbed solvent molecules were observed for the first time through operando infrared spectroscopy. A modified proton-exchange membrane reactor was used for observation, and the presence of Pd-H species was found to cause changes in the solvent's spectra.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Ryota Osuga, Mizuho Yabushita, Takeshi Matsumoto, Masato Sawada, Toshiyuki Yokoi, Kiyoshi Kanie, Atsushi Muramatsu
Summary: High-silica CHA-type aluminosilicates were synthesized hydrothermally in the absence of fluoride media, with the seed-assisted aging treatment playing a crucial role in the crystallization. These aluminosilicates exhibited a long catalytic lifetime and high selectivity towards lower olefins in the methanol-to-olefins reaction.
CHEMICAL COMMUNICATIONS
(2022)
