Article
Chemistry, Analytical
I. Nur Azreena, H. L. N. Lau, N. Asikin-Mijan, M. A. Hassan, Saiman Mohd Izham, E. Kennedy, M. Stockenhuber, M. S. Mastuli, Fahad A. Alharthi, Abdulaziz Ali Alghamdi, Y. H. Taufiq-Yap
Summary: This study found that La(10)zeo(90) catalyst exhibited excellent activity and selectivity in the hydrodeoxygenation of oleic acid, mainly attributed to the synergistic interaction between La-Si-Al, abundant weak+ medium acid sites, and excellent textural properties.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2021)
Article
Chemistry, Applied
Zijun Yang, Qiang Yu, Yonghua Guo, Xiaoxia Wu, Hua Wang, Jinyu Han, Qingfeng Ge, Xinli Zhu
Summary: Heteroatom metal-zeolite, specifically the Ti-Beta zeolites prepared using recrystallization and solid-state ion-exchange methods, exhibited differences in the distribution of Ti species and the presence of intra-crystallite mesopores. The ketonization reaction of propionic acid showed that Ti-Beta-Re had higher turnover frequency, lower apparent activation energy, and maintained higher selectivity of 3-pentanone compared to Ti-Beta-SSIE. This work demonstrated that tetrahedrally coordinated Ti species are the active sites for the ketonization reaction, and the presence of intra-crystallite mesopores facilitates the selective conversion of carboxylic acids.
MICROPOROUS AND MESOPOROUS MATERIALS
(2022)
Article
Chemistry, Applied
Zhucheng Yin, Xuejiao Qie, Maomao Zeng, Zhaojun Wang, Fang Qin, Jie Chen, Weiwei Li, Zhiyong He
Summary: The study found that chlorogenic acid binds to beta-casein mainly through hydrophobic interactions, with thermal treatment reducing the binding affinity between them but not affecting the secondary structure of beta-casein. Additionally, no covalent bond was observed in the complexes formed, and a synergistic effect was observed between beta-casein and chlorogenic acid in the assessment of antioxidant capacity in FRAP, while an antagonistic effect was seen in ABTS.
FOOD HYDROCOLLOIDS
(2022)
Article
Green & Sustainable Science & Technology
Shichao Gao, Shugang Wang, Yi Sun, Jihong Wang, Peiyu Hu, Jiaxu Shang, Zhenjun Ma, Yuntao Liang
Summary: Sorption thermal energy storage (STES) using zeolite 4A/water vapor as the working pairs has great potential for inter-seasonal thermal energy storage in building heating. In this study, a STES experimental bench was constructed, and charging/discharging experiments were conducted to analyze the thermal energy chain during the process. The results showed that a significant amount of thermal energy was lost through the reactor outlet during the charging process, hindering the improvement of thermal energy storage performance of the STES system. Additionally, it was found that higher charging temperature and lower charging air humidity could enhance the thermal energy storage performance.
Article
Chemistry, Physical
Alexander P. Spanos, Aamena Parulkar, Nicholas A. Brunelli
Summary: Enhancement of catalytic performance of zeolites can be achieved by controlling catalytic sites and reaction environment. Experimental results show that a hydrophobic framework is beneficial for alcohol ring opening of epoxides, with hydrophobic materials demonstrating higher turnover frequencies than hydrophilic catalysts under certain reaction conditions.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Physical
Magdalena Katarzyna Krol, Piotr Jelen
Summary: This study investigated the thermal stability and dehydration process of zeolite A using in situ high temperature Fourier transform infrared spectroscopy, revealing that water was gradually removed from the structure during heating and thermal degradation started as early as 550 degrees Celsius. The results contribute to the thermal analysis research of zeolite materials.
Article
Agriculture, Dairy & Animal Science
Niloufar Rafiee Tari, Zafir Gaygadzhiev, Anilda Guri, Amanda Wright
Summary: This study investigated the structural and functional properties of liquid MPC by adjusting pH and heat treatment conditions, finding that heating led to denaturation and aggregation of whey proteins, resulting in increased viscosity. Samples processed at higher pH showed significantly higher viscosity, while those treated at 85 degrees C for 5 min had higher viscosity than those at 125 degrees C for 15 s.
JOURNAL OF DAIRY SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
ZeynabAlsadat Khatami Shal, Cheuk-Wai Tai, Michael Goepel, Roger Glaeser, Mozaffar Shakeri
Summary: In-situ growth of supported embryonic TS-1 zeolite (<10nm) on a silica support was achieved by steam-assisted crystallization(SAC). The use of low amounts of TPABr and steam at a moderate temperature of 130 degrees C was the key factor to control partial transformation of silica into supported embryonic TS-1. Supported embryonic TS-1 exhibits higher catalytic activity, resistance to poisoning, and selectivity compared to reference crystalline TS-1.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Engineering, Electrical & Electronic
Weimin Xu, Shibo Li, Shujun Hu, Wenbo Yu, Yang Zhou
Summary: Ti3C2Tx MXene is a promising material for 5G communication applications due to its good thermal conductivity and microwave absorption properties. Annealing at 150 degrees Celsius can improve the microwave absorption properties, but prolonged annealing time may lead to performance degradation.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Energy & Fuels
Feng Yu, Chuanhao Zhang, Ruyi Geng, Haoxiang Zhou, Qi Dong, Shoujun Liu, Binbin Fan, Ruifeng Li
Summary: NiMo/gamma-Al2O3 catalysts with different hydrogenation functions were prepared and Beta zeolites with different acidity were synthesized. The influence of the metal-acid balance on the hydrocracking of naphthalene was investigated through the coupling of NiMo/gamma-Al2O3 catalysts with Beta zeolite. The catalytic performance of the coupled catalysts depended on the hydrogenation ability of NiMo/gamma-Al2O3 and the acidity of Beta zeolite, and the Si/Al ratio, crystal size, and amount of Beta zeolite greatly affected the hydrocracking performance.
Article
Energy & Fuels
S. Nogales-Delgado, A. Guiberteau, J. M. Encinar
Summary: The use of biodiesel as an alternative fuel has gained attention, with the quality being influenced by the properties of the raw materials used. Addition of antioxidants like TBHQ can prevent oxidation-related quality deterioration, ensuring stability during storage.
Article
Polymer Science
Tatjana Glaskova-Kuzmina, Didzis Dejus, Janis Jatnieks, Andrey Aniskevich, Jevgenijs Sevcenko, Anatolijs Sarakovskis, Aleksejs Zolotarjovs
Summary: This study aimed to investigate the effect of different post-printing cooling conditions on the mechanical and thermophysical properties of ULTEM (R) 9085 printed parts through FDM. Tensile tests, DMTA, and optical microscopy were conducted to analyze the samples printed in three orthogonal planes. The results showed little difference between samples cooled in the printer or oven, but a notable difference for samples cooled at room temperature. The Z printing direction exhibited the lowest mechanical performance and sensitivity to cooling conditions due to the anisotropic nature of FDM and debonding among layers.
Article
Materials Science, Multidisciplinary
Sara Valvez, Paulo N. B. Reis, Jose A. M. Ferreira
Summary: This study aims to analyse the annealing effect on the mechanical properties of PETG, carbon fibre reinforced PETG (PETG + CF) and Kevlar fibre reinforced PETG (PETG + KF). The final dimensions vary with temperature and exposure time regardless of the material, showing that the addition of fibres had no significant influence. The presence of fibres affects the radius of curvature, and this parameter is highly dependent on the type of fibre. Higher temperatures and exposure times generally lead to higher hardness values, achieving improvements of about 20% over untreated material. Bending properties increase with exposure time and temperature for composites, while in the case of neat PETG they increase with temperature and decrease with exposure time. After the annealing treatment, significant improvements were observed in bending strength, bending modulus, impact strength, stress relaxation, and creep behavior for all materials.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Multidisciplinary Sciences
Jiamin Yuan, Zhiqiang Liu, Yimo Wu, Jingfeng Han, Xiaomin Tang, Chengbin Li, Wei Chen, Xianfeng Yi, Jian Zhou, Rajamani Krishna, German Sastre, Anmin Zheng
Summary: Contrary to the general trend, the movement of long-chain molecules slows at higher temperatures under confinement due to the thermal resistance effect. This phenomenon limits molecular transportation in nanoscale channels, as confirmed by zero length column experiments. This study contributes to our understanding of anomalous diffusion and its mechanisms in confined systems.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Multidisciplinary
Shen Hu, Junru Liu, Guanghua Ye, Xinggui Zhou, Marc-Olivier Coppens, Weikang Yuan
Summary: A generalizable strategy has been developed to quantify the effect of surface barriers on zeolite catalysis using isomerization of n-pentane as a model system. Surface modification by SiO2 deposition was found to reduce surface barriers, improve diffusion, and increase catalytic activity of Pt/Beta catalyst. These results demonstrate that reducing surface barriers can effectively enhance zeolite catalyst performance affected by transport limitations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Marvin K. Sarango-Ramirez, Dae-Woon Lim, Daniil Kolokolov, Alexander E. Khudozhitkov, Alexander G. Stepanov, Hiroshi Kitagawa
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2020)
Article
Chemistry, Physical
Alexander E. Khudozhitkov, Alexander V. Toktarev, Sergei S. Arzumanov, Anton A. Gabrienko, Daniil I. Kolokolov, Alexander G. Stepanov
Article
Chemistry, Physical
Daniil I. Kolokolov, Dieter Freude, Alexander G. Stepanov
Summary: H-2 solid-state NMR is a reliable method for probing the dynamics and self-diffusion of molecules in porous materials like zeolites and metal-organic frameworks. It can provide valuable information on diffusion coefficients of different molecules within confined geometries. Comparisons with other experimental methods such as QENS and PFG NMR reveal both possibilities and limitations of H-2 NMR.
ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY
(2021)
Article
Chemistry, Physical
Anton A. Gabrienko, Alexander A. Kolganov, Sergei S. Arzumanov, Svetlana A. Yashnik, Vladimir V. Kriventsov, Dieter Freude, Alexander G. Stepanov
Summary: The study investigated the impact of different Cu(II) species loaded in zeolite on the activation of methane molecules for methane transformation to methanol. It was found that Cu2+ cations or [Cu-3(μ-O)3]2+ oxo-clusters could accelerate the H/D exchange reaction, indicating their promoting effect on the activation of methane C-H bonds by BAS. The formation of a transient molecular complex of methane with Cu(II) species prior to the H/D exchange reaction was also observed.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
William J. F. Trenholme, Daniil I. Kolokolov, Michelle Bound, Stephen P. Argent, Jamie A. Gould, Jiangnan Li, Sarah A. Barnett, Alexander J. Blake, Alexander G. Stepanov, Elena Besley, Timothy L. Easun, Sihai Yang, Martin Schroder
Summary: The desolvated metal-organic framework material MFM-160a shows excellent high-pressure uptake of CO2 and selective separation of C2 hydrocarbons from CH4, with experimental results consistent with theoretical predictions. Solid-state H-2 NMR spectroscopic studies reveal a low barrier and slow rotation rate of the phenyl group in the activated MOF, and the rotation rate increases with gas pressure due to weakening of an intramolecular hydrogen bond.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Nanoscience & Nanotechnology
Alexander E. Khudozhitkov, Hengli Zhao, Aziz Ghoufi, Sergei S. Arzumanov, Daniil Kolokolov, Guillaume Maurin, Alexander G. Stepanov
Summary: This study combines experimental and computational methods to reveal the diffusion mechanism of n-butane and 1-butene in ZIF-8. Different adsorption sites and motion modes of these hydrocarbons in ZIF-8 were identified through a combination of H-2 NMR technique and MD simulations.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Anton A. Gabrienko, Zoya N. Lashchinskaya, Sergei S. Arzumanov, Alexander Toktarev, Dieter Freude, Juergen Haase, Alexander G. Stepanov
Summary: Different Zn species and zeolite topology have varying effects on alkane aromatization reactions, with Zn2+ species showing greater efficiency. The presence of more Bronsted acid sites in ZnO/H-BEA promotes the hydrogenolysis pathway.
Article
Chemistry, Physical
Alexander E. Khudozhitkov, Sergei S. Arzumanov, Daniil Kolokolov, Alexander G. Stepanov
Summary: UiO-66 (Zr) is a thermally and chemically stable Zr-based metal-organic framework (MOF) with promising potential for separating n-butane and isobutane, showing significantly higher diffusion rate for n-butane compared to isobutane. This difference in diffusion barriers suggests high selectivity for kinetic-driven separation of the n-butane/isobutane mixture in UiO-66 (Zr)-based materials or membranes.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Anton A. Gabrienko, Zoya N. Lashchinskaya, Sergei S. Arzumanov, Alexander Toktarev, Dieter Freude, Juergen Haase, Alexander G. Stepanov
Summary: The kinetics of isobutane transformation on BEA zeolites modified with Zn2+ cations or ZnO clusters were investigated using H-1 MAS NMR spectroscopy, revealing that Zn2+/H-BEA exhibited higher rates for alkane dehydrogenation, hydrogenolysis, and aromatization compared to ZnO/H-BEA. Additionally, both zeolites were found to catalyze the reaction of isobutane with methane to yield propane. Kinetic analysis showed that Zn2+/H-BEA had higher activity for both n-butane and isobutane aromatization, with a greater preference for n-butane over isobutane transformation to aromatics.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Anton A. Gabrienko, Zoya N. Lashchinskaya, Sergei S. Arzumanov, Alexander Toktarev, Dieter Freude, Jurgen Haase, Alexander G. Stepanov
Summary: The impact of Zn2+ cations and ZnO small clusters on the conversion of isobutene to aromatic hydrocarbons on Zn-modified zeolites was investigated using C-13 MAS NMR and FTIR spectroscopy. Different reaction intermediates were identified at various temperatures, but similar pathways of isobutene transformation were observed on both zeolites at higher temperatures. The FTIR analysis revealed interactions of intermediate species with both Brønsted acid sites and Zn sites during each step of the olefin transformation.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Alexander E. Khudozhitkov, Masaki Donoshita, Alexander G. Stepanov, Frederik Philippi, Daniel Rauber, Rolf Hempelmann, Hiroshi Kitagawa, Daniil Kolokolov, Ralf Ludwig
Summary: The complex phase behavior of the glass forming protic ionic liquid has been reported using solid-state NMR spectroscopy, revealing evidence of tunneling driven mobility of hydrogen bonded moieties at high temperatures.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Physical
Alexander E. Khudozhitkov, Peter Stange, Alexander G. Stepanov, Daniil Kolokolov, Ralf Ludwig
Summary: We demonstrate that solid-state NMR spectroscopy is an effective tool for studying the structure, hydrogen bond dynamics, and phase transition behavior of protic ionic liquids (PILs). By analyzing the deuteron line shape and spin relaxation time, we obtain information about the structural and dynamical heterogeneity of the model PIL triethyl ammonium bis(trifluoromethanesulfonyl)amide [TEA][NTf2] in the solid state. The presence of different quadrupole coupling constants for the ND bond of the TEA cation indicates varying hydrogen bond strengths to the nitrogen and oxygen atoms of the NTf2 anion. We also provide insights into the transition processes and energetics of the solid and liquid states of the PIL.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Alexander E. E. Khudozhitkov, Sergei S. S. Arzumanov, Daniil I. I. Kolokolov, Alexander G. G. Stepanov
Summary: UiO-66 (Zr) is a metal-organic framework (MOF) with thermal and chemical stability that is widely used for adsorption-based applications. In this study, H-2 solid-state NMR was used to characterize the dynamics of UiO-66 in hydroxylated and dehydroxylated forms. The results showed that the dehydroxylated form had higher pi-flipping rate and phenylene ring plane librations. The diffusivity of butane isomers was also higher in the dehydroxylated form, which can be explained by the larger effective diameter of the window between cages in this form.
SOLID STATE NUCLEAR MAGNETIC RESONANCE
(2022)
Article
Chemistry, Physical
Alexander A. Kolganov, Anton A. Gabrienko, Ivan Yu Chernyshov, Alexander G. Stepanov, Evgeny A. Pidko
Summary: We conducted a detailed computational study on the reactivity of Zn-modified BEA zeolite towards C-H bond activation of methane. The results highlight the importance of representing the active site as a whole reactive ensemble that includes extra-framework Zn-EF(2+) cations, framework oxygens (O-F(2-)), and zeolite pores. Our findings suggest that the acid properties of the localized extra-framework cations can only provide a rough assessment of the reactivity of cations in metal-containing zeolites. However, there is a correlation between the activation energy and pyrrole adsorption energy.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Alexander E. Khudozhitkov, Sergei S. Arzumanov, Alexander Toktarev, Svetlana Cherepanova, Anton A. Gabrienko, Daniil Kolokolov, Alexander G. Stepanov
Summary: The relationship between water adsorption on MIL-53 (Al) MOF, the structural phase of MIL-53 (Al), and the quadrupole coupling constant of Al-27 framework aluminium atom (QCC) was investigated using solid-state Al-27 MAS NMR spectroscopy, XRD analysis, and DFT calculations. It was found that Al-27 QCC is primarily sensitive to water adsorption on the Al-sites and to a lesser extent to the framework contraction/expansion interconversions. The study concludes that Al-27 MAS NMR method is sensitive enough to differentiate the effects of pore contractions and water adsorption on Al-sites based on changes in the QCC value.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
