Article
Chemistry, Physical
Jawaher Mosrati, Ali M. Abdel-Mageed, Thanh Huyen Vuong, Reni Grauke, Stephan Bartling, Nils Rockstroh, Hanan Atia, Udo Armbruster, Sebastian Wohlrab, Jabor Rabeah, Angelika Brueckner
Summary: Cu single-atom catalysts supported on CeO2-TiO2 were prepared using a sol-gel method and showed high efficiency and stability in CO oxidation. Spectroscopic methods such as infrared, electron paramagnetic resonance, and X-ray photoelectron spectroscopy revealed the mechanism of action and structure-reactivity relationships.
Article
Energy & Fuels
Heng Xie, Daobing Shu, Tianhu Chen, Haibo Liu, Xuehua Zou, Can Wang, Zhengyan Han, Dong Chen
Summary: Manganese-doped FeVO4 catalysts were synthesized using a novel one-pot method, and the effect of Mn doping on FeVO4 in the selective catalytic reduction of NOx with NH3 was studied extensively. The 0.3Mn-FeV catalyst demonstrated superior deNOx performance, reaching 100% NOx conversion rate at 250 degrees C. Various characterization techniques revealed that Mn doping improved the crystal size, acidity, and redox properties of the catalyst, facilitating NH3 activation and maintaining V species in a higher oxidation state for enhanced performance in the SCR reaction.
Article
Chemistry, Physical
Sonja Keller, Ursula Bentrup, Jabor Rabeah, Angelika Brueckner
Summary: Ce1-xMxO2-3 solid solutions (M = Fe3+, Bi3+, Sb3+; x = 0.01, 0.03, 0.05) with and without VOy surface species were characterized and tested in low-temperature NH3-SCR of NOx. The active sites and structure-reactivity relationships were identified through in situ DRIFTS and EPR measurements. It was found that the catalysts with VOy surface species exhibited higher activity compared to the ones without VOy. The efficiency of the V5+/V4+ redox shuttle and surface acidity also influenced the catalytic activity.
JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Physical
Shunsaku Yasumura, Yucheng Qian, Taisetsu Kato, Shinya Mine, Takashi Toyao, Zen Maeno, Ken-ichi Shimizu
Summary: The reduction/oxidation half-cycles of Fe-exchanged mordenite zeolites for NH3-SCR of NO were investigated using in situ/operando spectroscopy and density functional theory calculations. The mechanism involves the reduction of Fe3+ to Fe2+ under NO and NH3 exposure, followed by the reoxidation of Fe2+ under O2 or NO + O2. Fe-zeolites with a higher number of Bronsted acid sites showed the highest NOx conversion.
Article
Chemistry, Physical
Hongyan Xue, Xiaoming Guo, Tao Meng, Dongsen Mao, Zhen Ma
Summary: M/ZSM-5 (M = Mn, Co, Cu) samples were prepared by impregnation and their catalytic performance in NH3-SCR of NO was tested. Cu/ZSM-5 exhibited the highest activity, followed by Mn/ZSM-5, and Co/ZSM-5 was the least active. In-situ DRIFTS analysis revealed the nature and evolution of surface species. Coordinated NH3, NH4+, and amide (-NH2) species derived from NH3 adsorption were found to be relevant for NH3-SCR, while bridged nitrate species derived from NOx adsorption were identified as the main active species. Bridged nitrate was more abundant and thermally more stable on Cu/ZSM-5, consistent with its higher activity compared to Mn/ZSM-5 and Co/ZSM-5. Different mechanisms, including Eley-Rideal and Langmuir-Hinshelwood, were observed for Mn/ZSM-5 at different temperatures, while both pathways coexisted for Co/ZSM-5 and Cu/ZSM-5.
SURFACES AND INTERFACES
(2022)
Article
Chemistry, Physical
Tianyu Liu, Ruijie Yang, Guomeng Zhang, Weihong Wu, Zhengda Yang, Riyi Lin, Xinwei Wang, Ye Jiang
Summary: The reaction mechanism over CeO2-TiO2 catalyst involves both E-R and L-H mechanisms, with NH2NO species playing a key role as an intermediate. DFT calculations provide insights into the adsorption energy, activation energy barrier, and reaction heat for various steps in the process.
APPLIED SURFACE SCIENCE
(2021)
Article
Engineering, Environmental
Yong Jia, Jin Jiang, Ruizi Zheng, Lina Guo, Jing Yuan, Shule Zhang, Mingyan Gu
Summary: Phosphomolybdic acid catalyst (PMoA/TiO2) is a promising catalyst for NH3-SCR due to its strong acidity and redox property. The NH3-SCR reaction over PMoA/TiO2 follows Eley-Rideal and Langmuir-Hinshelwood mechanisms, with key intermediates NH2, NH2NO, HNNOH, and HO2NNH. Rate-controlling steps involve NH3 dissociation, internal hydrogen transfer, and HO2NNH formation. Standard and fast SCR make up the catalytic cycle of NH3-SCR over PMoA.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Chemistry, Physical
Xinwei Ye, Ramon Oord, Matteo Monai, Joel E. Schmidt, Tiehong Chen, Florian Meirer, Bert M. Weckhuysen
Summary: This study investigates the surface changes of Cu-ZSM-5 zeolite catalyst in the NH3-SCR reaction using in situ spectroscopy. It is found that Cu2+ forms complexes with NH3 at low temperatures and facilitates the reaction by forming high coverage nitrate intermediates. After steam treatment, [Cu-x(OH)(2x-1)](+) oligomers/clusters accumulate on the Cu-ZSM-5 surface, strongly adsorbing NH3 and nitrates/nitric acid at low temperatures, limiting the reaction. Additionally, NH3 and nitrates/nitric acid compete for shared adsorption sites, and selective tuning is achieved by prompt removal of nitrates/nitric acid with NO.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Guangyan Xu, Honghong Wang, Yunbo Yu, Hong He
Summary: The study revealed the presence of various silver species on Ag/Al2O3 catalysts, with metallic silver clusters identified as the active sites for nitrate formation and the reduction of silver nitrates being the rate-determining step in the H-2-NH3-SCR reaction.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Physical
Rob Jeremiah G. Nuguid, Martin Elsener, Davide Ferri, Oliver Krocher
Summary: Hydrogen cyanide is a highly toxic gas formed through the reaction between formaldehyde and ammonia in exhaust. The molecular mechanism leading to the release of HCN is yet to be fully understood, with recent studies detecting cyanide intermediate species on the catalyst surface. Insights into the catalytic process can help develop mitigation measures for reducing HCN emissions.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Chemistry, Applied
Hiroe Kubota, Chong Liu, Takehiro Amada, Kenichi Kon, Takashi Toyao, Zen Maeno, Kakuya Ueda, Atsushi Satsuma, Nao Tsunoji, Tsuneji Sano, Kenichi Shimizu
Summary: The study investigates the reaction mechanism of NH3-SCR catalyzed by a phosphorus-modified CHA zeolite with active Cu species, revealing that the process involves reduction and reoxidation of Cu species. The phosphorus modification is found to enhance the hydrothermal durability of the catalyst, preserving more redox-active Cu species and the zeolite framework.
Article
Chemistry, Physical
Daniyal Kiani, Yuanzhou Xi, Nathan Ottinger, Z. Gerald Liu
Summary: Reactor-based NH3 TPD and temporally resolved in situ DRIFTS were used to study NH3-catalyst interactions. It was found that an unexpected reaction occurred during NH3 adsorption, involving acid-base pair sites in zeolite catalysts. This reaction was found to occur at different rates on different catalysts.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Environmental
Ningqiang Zhang, Jiahuan Tong, Shinta Miyazaki, Shirun Zhao, Hiroe Kubota, Yuan Jing, Shinya Mine, Takashi Toyao, Ken-ichi Shimizu
Summary: This study investigates the active sites and reaction mechanism for the selective catalytic reduction of NO by NH3 over phosphate-loaded ceria catalysts. The results reveal the presence of H3PO4 and H2P2O6 species on the catalysts, which interact with Ce4+(OH-) species and undergo reduction/oxidation half-cycles to produce N2, H2O, and Ce3+ species.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Lijun Liu, Tao Liu, Yajin Zhou, Xiaotao Zheng, Sheng Su, Jiuyang Yu, Jun Xiang
Summary: The reaction of NO with NH3 over Mn/Ti catalyst in the presence of CO was studied, and it was found that CO can significantly decrease the NOx conversion between 100 and 300 degrees C and improve the N2 selectivity, especially above 200 degrees C. The presence of CO can compete with NO for adsorption on the catalyst, leading to a decrease in NH3 adsorption on weakly acid sites and a subsequent decrease in NOx conversion at low temperature.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Yang Gao, Li Cao, Xiaodong Wu, Xu Zhang, Ziran Ma, Rui Ran, Zhichun Si, Duan Weng, Baodong Wang
Summary: CeNbTi catalyst was poisoned by sulfur in different atmospheres, and the addition of NH3 effectively inhibited catalyst deactivation. The roles of NH3 in removing surface sulfates were studied using TPD analysis and DRIFTS experiments, and it was found that ammonium sulfates were generated under certain conditions.
Article
Chemistry, Multidisciplinary
Thirusangumurugan Senthamarai, Vishwas G. Chandrashekhar, Nils Rockstroh, Jabor Rabeah, Stephan Bartling, Rajenahally Jagadeesh, Matthias Beller
Summary: Functionalized (hetero)aromatic compounds are important chemicals used in basic and applied sciences. The catalytic oxidation of alcohols is a green and cost-effective process, and this study reports the synthesis of graphitic layers encapsulated in cobalt-piperazine-tartaric acid complex nanoparticles as an oxidation catalyst.
Article
Chemistry, Multidisciplinary
Michael Traxler, Susanne Reischauer, Sarah Vogl, Jerome Roeser, Jabor Rabeah, Christopher Penschke, Peter Saalfrank, Bartholomaeus Pieber, Arne Thomas
Summary: The multicomponent approach is used to create bifunctional materials for cooperative catalysis by incorporating multiple functionalities into a single covalent organic framework (COF). These COFs have a well-defined structure for structure-activity relationship studies. Nickel-loaded COFs containing acridine and 2,2'-bipyridine linkers connected through 1,3,5-benzenetrialdehyde derivatives are reported. The acridine motif enables broad light absorption, while the bipyridine unit allows complexation of nickel catalysts, making the framework materials suitable for light-mediated carbon-heteroatom cross-couplings. Switching between high charge-carrier mobility and charge-separated species can be achieved by varying the node units, tailoring the materials for specific reactions. Nickel-loaded COFs are recyclable and can catalyze cross-couplings using red light irradiation.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Thea S. Mayer, Tobias Taeufer, Sina Brandt, Jabor Rabeah, Jola Pospech
Summary: In this study, we demonstrate a photomediated hydro- and deuterodecarboxylation of carboxylic acids using an organic pyrimidopteridine photoredox catalyst. The reaction was optimized using a statistical design of experiment and successfully converted NSAID tablets and larger quantities. This method can be applied to primary, secondary, and tertiary aliphatic biologically active carboxylic acids with high deuterium incorporation.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Biochemical Research Methods
Robert Jungnickel, Francesca Mirabella, Joerg Manfred Stockmann, Joerg Radnik, Kannan Balasubramanian
Summary: This study presents an optimized preparation strategy for graphene-coated surface plasmon resonance chips, allowing them to be annealed at high temperatures without deterioration of surface morphology. The annealing process improves spectral response and refractive index sensitivity. The sensors demonstrate applicability in studying binding kinetics and can be reused multiple times.
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Abdallah I. M. Rabee, Dan Zhao, Sebastian Cisneros, Carsten R. Kreyenschulte, Vita Kondratenko, Stephan Bartling, Christoph Kubis, Evgenii Kondratenko, Angelika Brueckner, Jabor Rabeah
Summary: Gold-based catalysts with low gold loading supported on TiO2 and ZrO2 were synthesized and characterized. The Au/TiO2 catalyst showed higher activity than Au/ZrO2 at 250℃, with different reaction mechanisms involved.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Chemistry, Multidisciplinary
Xingchao Dai, Xinzhi Wang, Carsten Kreyenschulte, Hangkong Yuan, Angelika Brueckner, Feng Shi, Jabor Rabeah
Summary: Value-added formamides were synthesized sustainably by catalyzing in situ C-C bond cleavage with zeolite 5A supported Cu-based catalysts using glycerol derivatives as the carbonyl source. The introduction of Zr-IV ions greatly increased the activity of the Cu/5A catalyst. Isotopic tracing experiments confirmed the involvement of glycerol derivatives in the formation of formamide products.
Article
Chemistry, Multidisciplinary
Prasenjit Das, Gouri Chakraborty, Jerome Roeser, Sarah Vogl, Jabor Rabeah, Arne Thomas
Summary: In this study, different functionalities were introduced into highly stable covalent organic frameworks (COFs) using multicomponent reactions (MCRs). Four chemically stable quinoline-4-carboxylic acid DMCR-COFs equipped with an acid-base bifunctionality were successfully synthesized. These DMCR-COFs exhibited superior photocatalytic H2O2 evolution compared to the imine COF analogue. Furthermore, they showed high photostability, durability, and recyclability, making them a promising materials' platform for solar to chemical energy conversion.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Qiyang Zhang, Jabor Rabeah, Thanh Huyen Vuong, Tatiana Otroshchenko, Evgenii V. Kondratenko
Summary: The metathesis reaction of ethylene and 2-butene to produce propene is widely used in the chemical industry. MoOx-based supported catalysts show potential as alternatives to the currently employed WOx-containing systems. The activity of these catalysts depends on the formation of active Mo-carbene sites, which can be controlled by promoting the support with small amounts of alkali or alkaline earth metal oxides. The electronegativity of the additives affects olefin adsorption and carbene formation.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Bishal Boro, Ratul Paul, Hui Ling Tan, Quang Thang Trinh, Jabor Rabeah, Chia-Che Chang, Chih-Wen Pao, Wen Liu, Nam-Trung Nguyen, Binh Khanh Mai, John Mondal
Summary: In this study, a unique metalated porous organic polymer was synthesized using a cost-effective approach, and it exhibited superior catalytic performance for low-temperature reactions in water. The polymer addressed some drawbacks of conventional catalytic systems.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Ali M. Abdel-Mageed, Bunyarat Rungtaweevoranit, Sarawoot Impeng, Joachim Bansmann, Jabor Rabeah, Shilong Chen, Thomas Haering, Supawadee Namuangrak, Kajornsak Faungnawakij, Angelika Brueckner, R. Juergen Behm
Summary: Elucidating the reaction mechanism of CO oxidation using a molecularly defined copper single-atom catalyst supported by UiO-66 metal-organic framework (Cu/UiO-66) was achieved through a combination of in situ/operando spectroscopies, kinetic measurements, and density-functional-theory-based calculations. The study identified the active site, reaction intermediates, and transition states of the dominant reaction cycle, as well as changes in oxidation/spin state during the reaction. The reaction involves the continuous dissociation of adsorbed O-2, leading to the formation of an O atom connecting the Cu center with a neighboring Zr4+ ion as the rate-limiting step.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Chenyang Wang, Phong Dam, Mohamed Elghobashy, Angelika Brueckner, Jabor Rabeah, Luis Miguel Azofra, Osama El-Sepelgy
Summary: In this study, a biomimetic method for the catalytic deammoniation of diverse primary amines is presented. This method offers operational simplicity and high selectivity, providing a rapid pathway to olefin products derived from nonfossil-based chemicals. The use of acridinium salt and cobaloxime as readily available photoactive catalysts enables this unconventional dehydroamination process.
Article
Chemistry, Physical
Shuoping Ding, Jose Balena Gabriel Filho, Tim Peppel, Simon Haida, Jabor Rabeah, Norbert Steinfeldt, Jennifer Strunk
Summary: Two-dimensional ZnIn2S4 nanosheets were synthesized via a trisodium citrate-assisted hydrothermal method and used for the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) and 5-formyl-2-furan (FFCA) with atmospheric O-2 under visible light irradiation. The conversion of HMF reached 95%, and the DFF selectivity was 70% after 1.5 h of illumination. Photogenerated holes (h(+)), O-2(-) and carbon-centred radicals are the dominant reaction species.
SUSTAINABLE ENERGY & FUELS
(2023)
Article
Chemistry, Physical
Shuoping Ding, Igor Medic, Norbert Steinfeldt, Tianao Dong, Tim Voelzer, Simon Haida, Jabor Rabeah, Juncheng Hu, Jennifer Strunk
Summary: Constructing hierarchical and ultrathin-structured metal sulfides is beneficial for efficient hydrogen evolution catalysts. In this study, ZnIn2S4 hollow nanoflowers composed of ultrathin nanosheets were creatively synthesized through a trisodium citrate-mediated and stirring-assisted solvothermal method. The optimized ZnIn2S4 hollow nanoflowers exhibited a high photocatalytic hydrogen generation rate and can be obtained without the need for a cocatalyst.
Article
Chemistry, Multidisciplinary
Chenyang Wang, Luis Miguel Azofra, Phong Dam, Edelman J. Espinoza-Suarez, Hieu Trung Do, Jabor Rabeah, Angelika Brueckner, Osama El-Sepelgy
Summary: In this study, an intramolecular endo-selective Heck reaction of iodomethylsilyl ethers of phenols and alkenols was reported. The reaction resulted in the formation of seven- and eight-membered siloxycycles in excellent yields, which could be further converted into the corresponding allylic alcohols upon oxidation. This method could be used for the selective (Z)-hydroxymethylation of o-hydroxystyrenes and alkenols. Rapid scan EPR experiments and DFT calculations suggested a concerted beta-hydrogen elimination event to take place in the triplet state.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Prasenjit Das, Gouri Chakraborty, Jerome Roeser, Sarah Vogl, Jabor Rabeah, Arne Thomas
Summary: Multicomponent reactions (MCRs) are employed to incorporate different functionalities into stable covalent organic frameworks (COFs). In this study, irreversible three-component Doebner reaction is utilized to synthesize chemically stable DMCR-COFs equipped with acid-base bifunctionality. These DMCR-COFs exhibit superior photocatalytic H2O2 evolution compared to Imine-1, showcasing their potential as materials for solar to chemical energy conversion.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
