Publications by authors named "Vladimir Martis"

Asphalt-surfaced areas such as roads have been reported as major non-combustion sources of reactive organic compounds in urban areas. Emission of latter compounds from asphalt is exacerbated due to exposure to sunlight and high temperature, contributing to negative human and environmental health outcomes. Furthermore, loss of asphalt components over time is linked to bitumen's aging that reduces service life of roads.

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  • Researchers investigated two metal-organic frameworks, MIL-53(Al)-TDC and MIL-53(Al)-BDC, for their ability to adsorb sulfur oxides (SO).
  • MIL-53(Al)-TDC showed rigidity during SO adsorption, while MIL-53(Al)-BDC displayed flexibility with multiple pore sizes allowing for different adsorption phases.
  • Both frameworks demonstrated excellent performance for SO capture, even in humid conditions, suggesting their potential use in SO sensing and storage/transportation applications.
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  • This study explores the use of porous organic cages (POCs) for capturing sulfur oxides (SO), which is a challenging task.
  • Three different N-containing cage materials were analyzed, revealing varying levels of SO capture abilities.
  • Among them, the tertiary amine POC (6FT-RCC3) was the most effective, capturing a high amount of SO while maintaining excellent reversibility over many cycles, and various techniques were used to study their adsorption behavior.
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NOTT-401 was found to be a highly stable adsorbent for SO2 and CO with excellent cyclability and a straightforward regeneration at room temperature. Moreover, the preferential CO binding sites within the MOF material have been identified by experimental in situ DRIFT spectroscopy coupled with DFT and QTAIM calculations. Such preferential CO adsorption sites were correlated to identify the most significant SO2 interactions within NOTT-401.

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A new material, MOF-type [Ir]@NU-1000, was accessed from the incorporation of the iridium organometallic fragment [Ir{κ(P,Si,Si)PhP(-CHCHSiPr)}] into NU-1000. The new material incorporates less than 1 wt % of Ir(III) (molar ratio Ir to NU-1000, 1:11), but the heat of adsorption for SO is significantly enhanced with respect to that of NU-1000. Being a highly promising adsorbent for SO capture, [Ir]@NU-1000 combines exceptional SO uptake at room temperature and outstanding cyclability.

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Article Synopsis
  • Research on CAU-10 reveals efficient adsorption of sulfur dioxide (SO) using both experimental and computational methods.
  • The study identifies that van der Waals interactions play a crucial role in the adsorption process.
  • Findings suggest that CAU-10 is a highly effective material for capturing sulfur dioxide.
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Postsynthetic functionalization of magnesium 2,5-dihydroxyterephthalate (Mg-MOF-74) with tetraethylenepentamine (TEPA) resulted in improved CO adsorption performance under dry and humid conditions. XPS, elemental analysis, and neutron powder diffraction studies indicated that TEPA was incorporated throughout the MOF particle, although it coordinated preferentially with the unsaturated metal sites located in the immediate proximity to the surface. Neutron and X-ray powder diffraction analyses showed that the MOF structure was preserved after amine incorporation, with slight changes in the lattice parameters.

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Polymers that possess highly nucleophilic pyrrolidinopyridine (Pyr) and primary amino (vinylamine, VAm) groups were prepared by free-radical copolymerization of N,N-diallylpyridin-4-amine (DAAP) and N-vinylformamide (NVF) followed by acidic hydrolysis of NVF into VAm. The resulting poly(DAAP-co-VAm-co-NVF) copolymers were water-soluble and reacted with water-dispersible polyurethane possessing a high content of unreacted isocyanate groups. Spray-coating of the nylon-cotton (NYCO), rayon, and poly(p-phenylene terephthalamide) (Kevlar 119) fibers pretreated with phosphoric acid resulted in covalent bonding of the polyurethane with the hydroxyl groups on the fiber surface.

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Energy-resolved electron-yield X-ray absorption spectroscopy is a promising technique for probing the near-surface structure of nanomaterials because of its ability to discriminate between the near-surface and bulk of materials. So far, the technique has only been used in model systems. Here, the local structural characterization of nanoporous cobalt-substituted aluminophosphates is reported and it is shown that the technique can be employed for the study of open-framework catalytically active systems.

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A high-pressure gas rig for in situ catalytic reactions at X-ray absorption spectroscopy beamline (BM26A) has been developed. The rig enables catalysts to be studied in a variety of cells under well controlled and industrially relevant operation conditions. A large variety of gas mixtures can be generated and pressures of up to 50 bar with dry gas and 20 bar with wet gas (steam) can be obtained.

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In this paper, we report a detailed characterisation of chromium doped iron oxide catalysts using a range of techniques to establish the nature of chromium species in the near surface and bulk of iron oxide, high-temperature shift (HTS) catalysts. In particular we have employed X-ray absorption spectroscopy Cr K-edge near edge and extended fine structure data for comparison with chemical and X-ray photoelectron spectroscopy. There was excellent agreement between the techniques in terms of identification and quantification of Cr(6+) and Cr(3+) species as a function of calcination temperatures between 100 and 500 °C.

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Combination of in situ Raman scattering with high-resolution XRD and XAS techniques has proven to be a powerful tool to elucidate the crystal growth of gamma-Bi2MoO6 under hydrothermal conditions.

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