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The understanding of the catalyst-support interactions has been an important challenge in heterogeneous catalysis since the supports can play a vital role in controlling the properties of the active species and hence their catalytic performance. Herein, a series of isostructural mesoporous metal-organic frameworks (MOFs) based on transition metals, lanthanides, and actinides (Zr, Hf, Ce, Th) were investigated as supports for a vanadium catalyst. The vanadium species was coordinated to the oxo groups of the MOF node in a single-ion fashion, as determined by single-crystal X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, and diffuse reflectance UV-vis spectroscopy. The support effects of these isostructural MOFs were then probed using the aerobic oxidation of 4-methoxybenzyl alcohol as a model reaction. The turnover frequency was found to be correlated with the electronegativity and oxidation state of the metal cations on the supporting MOF nodes, highlighting an important consideration when designing catalyst supports.
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http://dx.doi.org/10.1021/jacs.9b02603 | DOI Listing |
J Colloid Interface Sci
December 2024
School of Chemical Engineering, North China University of Science and Technology, Tangshan 063009, China. Electronic address:
Transition metal oxides (TMOs) can accelerate the sluggish kinetics of vanadium redox reaction, but face challenges like limited active sites and difficulties in nanometerization, highlighting the urgent need for new TMO electrocatalysts for vanadium redox flow battery (VRFB). CoMoO features high electrochemical activity, numerous redox sites, flexible control, and short electron pathways. Herein, a high catalytic and super stable graphite felt electrode modified in situ with network cross-linking CoMoO nanosheets (CoMoO@GF) was prepared via hydrothermal and heat treatment method to enhance VRFB performance.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Tsinghua University, Graduate School at Shenzhen, Tsinghua Campus, The University Town, 518055, Shenzhen, CHINA.
Vanadium flow battery (VFB) promises a route for achieving grid-scale power storage by harnessing renewable energy sources. However, the sluggish reaction kinetics of vanadium redox couples and serious hydrogen evolution reaction (HER) still restrict the further development of VFB. Addressing these challenges requires not only effective solutions but also ones that are cost-efficient and scalable to meet the demands of affordable energy storage.
View Article and Find Full Text PDFNature
December 2024
PSI Center for Photon Science, Villigen, Switzerland.
The functionality of materials is determined by their composition and microstructure, that is, the distribution and orientation of crystalline grains, grain boundaries and the defects within them. Until now, characterization techniques that map the distribution of grains, their orientation and the presence of defects have been limited to surface investigations, to spatial resolutions of a few hundred nanometres or to systems of thickness around 100 nm, thus requiring destructive sample preparation for measurements and preventing the study of system-representative volumes or the investigation of materials under operational conditions. Here we present X-ray linear dichroic orientation tomography (XL-DOT), a quantitative, non-invasive technique that allows for an intragranular and intergranular characterization of extended polycrystalline and non-crystalline materials in three dimensions.
View Article and Find Full Text PDFInorg Chem
December 2024
Department of Chemistry, University of Rochester, Rochester, New York 14627, United States.
Understanding how modification of molecular structures changes the thermochemistry of H atom uptake can provide design criteria for the formation of highly active catalysts for reductive transformations. Herein, we describe the effect of doping an atomically precise polyoxotungstate with vanadium on proton-coupled electron transfer (PCET) reactivity. The Lindqvist-type polyoxotungstate [WO] displays reversible redox chemistry, which was found to be unchanged in the presence of acid, indicating an inability to couple reduction with protonation.
View Article and Find Full Text PDFJ Hazard Mater
November 2024
State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; Sino-German Centre for Water and Health Research, Sichuan University, Chengdu 610065, China.
Coupling extra electron supply with iron-mediated advanced oxidation processes (AOPs) is an efficient strategy for long-lasting oxidation of organic contaminants in environmental remediation. Many subsequent attempts have been made, such as homogeneous catalysts and metal catalysts, of which secondary organic pollution and surface passivation layers limit their application. In this work, metal borides as co-catalysts can efficiently accelerate the Fenton reaction by firmly sacrificing electrons to Fe(III) reduction.
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