The commercially available zeolite HY and its desilicated analogue were subjected to a classical wet impregnation procedure with NHVO to produce catalysts differentiated in acidic and redox properties. Various spectroscopic techniques (in situ probe molecules adsorption and time-resolved propane transformation FT-IR studies, XAS, V MAS NMR, and 2D COS UV-vis) were employed to study speciation, local coordination, and reducibility of the vanadium species introduced into the hierarchical faujasite zeolite. The acid-based redox properties of V centres were linked to catalytic activity in the oxidative dehydrogenation of propane. The modification of zeolite via caustic treatment is an effective method of adjusting its basicity-a parameter that plays an important role in the ODH process. The developed mesopore surface ensured the attachment of vanadium species to silanol groups and formation of isolated (SiO)(HO)V=O and (SiO)V=O sites or polymeric, highly dispersed forms located in the zeolite micropores. The higher basicity of HY, due to the presence of the Al-rich shell, aided the activation of the C-H bond leading to a higher selectivity to propene. Its polymerisation and coke formation were inhibited by the lower acid strength of the protonic sites in desilicated zeolite. The Al-rich shell was also beneficial for anchoring V species and thus their reducibility. The operando UV-vis experiments revealed higher reactivity of the bridging oxygens V-O-V over the oxo-group V=O. The (SiO)V=O species were found to be ineffective in propane oxidation when temperature does not exceed 400 °C.
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http://dx.doi.org/10.3390/ijms23105584 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
KU Leuven: Katholieke Universiteit Leuven, Chemistry, BELGIUM.
Understanding the impact of oxidative modification on protein structure and functions is essential for developing therapeutic strategies to combat macromolecular damage and cell death. However, selectively inducing oxidative modifications in proteins remains challenging. Herein we demonstrate that [V6O13{(OCH2)3CCH2OH}2]2- (V6-OH) hybrid metal-oxo cluster can be used for selective protein oxidative cleavage and modifications.
View Article and Find Full Text PDFISA Trans
December 2024
Group of Power Systems, Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre, 1, 08930, Sant Adrià del Besòs, Spain. Electronic address:
This paper presents the design and implementation of a deep-learning-based observer for accurately estimating the State of Charge (SoC) of a vanadium flow battery. The novelty of the proposal lies in its direct use of terminal voltage and the application of a machine learning algorithm to model the battery's overpotentials, leading to greater accuracy and reduced complexity compared to classical models. The overpotentials model consists of a neural network trained using data generated by a classical observer that estimates species concentration using a physical electrochemical model and the open-circuit voltage measurement.
View Article and Find Full Text PDFJ Trace Elem Med Biol
January 2025
Department of Pathology, College of Medicine, King Khalid University, Asir 61421, Saudi Arabia; Department of Forensic Medicine and Clinical Toxicology, Mansoura University, Egypt.
Background: Vanadium (VAN) is a significant trace element, but its higher exposure is reported to cause severe organ toxicity. Tectochrysin (TEC) is a naturally derived flavonoid which demonstrates a wide range of pharmacological properties.
Aim: The current study was planned to assess the cardioprotective potential of TEC against VAN induced cardiotoxicity in rats via regulating biochemical, and histological profile.
Chemistry
January 2025
Ningbo University, School of Material Science and Chemical Engineering, Rokkakubashi, Kanagawa-ku, Yokohama-shi, Kanagawa, 221-8686, Japan., 315211, Ningbo, CHINA.
Direct oxidation of methane to methanol utilizing molecular oxygen under mild conditions is an important yet challenging process due to the difficulty in activation of methane under such conditions. In this research, we report zeolitic octahedral metal oxides based on cobalt vanadotungstates, which act as the catalysts for oxidation of methane using molecular oxygen as the oxidant without co-reductants at a low temperature of 90 oC even as low as 60 oC. This catalytic process results in the high-yield production of methanol as the major product.
View Article and Find Full Text PDFNat Commun
January 2025
Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China.
Compared with widely established monovalent-ion batteries, aqueous multivalent-ion batteries promise higher capacity release by achieving multiple electron-transfer events per ion intercalation in the host material. Despite plausibility, this high-capacity dream is untenable with the total tolerable redox charge-transfer limit of the host material for all carrier species equally, which is historically assumed to depend on the material rather than the guest carrier itself, and the kinetic hysteresis induced by larger charge/radius ratios induced kinetic hysteresis further enlarges the divide. Herein, we report that copper carrier redox in vanadium sulfide (VS) exceeds the intrinsic intercalation capacity boundary, with the highest capacity release as 675 mAh g at 0.
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