A study of the reactions of liquid acetone and toluene on transition metal hydrides, which can be used in thermal energy or hydrogen storage applications, is presented. Hydrogen is confined in TiFe, Ti0.95Zr0.05Mn1.49V0.45Fe0.06 ("Hydralloy C5"), and V40Fe8Ti26Cr26 after contact with acetone. Toluene passivates V40Fe8Ti26Cr26 completely for hydrogen desorption while TiFe is only mildly deactivated and desorption is not blocked at all in the case of Hydralloy C5. LaNi5 is inert toward both organic liquids. Gas chromatography (GC) investigations reveal that CO, propane, and propene are formed during hydrogen desorption from V40Fe8Ti26Cr26 in liquid acetone, and methylcyclohexane is formed in the case of liquid toluene. These reactions do not occur if dehydrogenated samples are used, which indicates an enhanced surface reactivity during hydrogen desorption. Significant amounts of carbon-containing species are detected at the surface and subsurface of acetone- and toluene-treated V40Fe8Ti26Cr26 by X-ray photoelectron spectroscopy (XPS). The modification of the surface and subsurface chemistry and the resulting blocking of catalytic sites is believed to be responsible for the containment of hydrogen in the bulk. The surface passivation reactions occur only during hydrogen desorption of the samples.
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http://dx.doi.org/10.1021/acsami.6b05537 | DOI Listing |
ChemSusChem
December 2024
Green Carbon Research Center, Korea Research Institute of Chemical Technology, Daejeon, 34114, Republic of Korea.
Pentose oxidation and reduction, processes yielding value-added sugar-derived acids and alcohols, typically involve separate procedures necessitating distinct reaction conditions. In this study, a novel one-pot reaction for the concurrent production of xylonic acid and xylitol from xylose is proposed. This reaction was executed at ambient temperature in the presence of a base, eliminating the need for external gases, by leveraging Pt-supported catalysts.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Institute of Physical Chemistry-Ilie Murgulescu of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania.
Bimetallic (Ta/Ti, V, Co, Nb) mesoporous MCM-41 nanoparticles were obtained by direct synthesis and hydrothermal treatment. The obtained mesoporous materials were characterized by XRD, XRF, N adsorption/desorption, SEM, TEM, XPS, Raman, UV-Vis, and PL spectroscopy. A more significant effect was observed on the mesoporous structure, typically for MCM-41, and on optic properties if the second metal (Ti, Co) did not belong to the same Vb group with Ta as V and Nb.
View Article and Find Full Text PDFAdv Mater
December 2024
School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China.
Carbon-supported single-atom catalysts exhibit exceptional properties in acidic CO reduction. However, traditional carbon supports fall short in building high-site-utilization and CO-rich interfacial environments, and the structural evolution of single-atom metals and catalytic mechanisms under realistic conditions remain ambiguous. Herein, an interconnected mesoporous carbon nanofiber and carbon nanosheet network (IPCF@CS) is reported, derived from microphase-separated block copolymer, to improve catalytic efficiency of isolated Ni.
View Article and Find Full Text PDFInorg Chem
December 2024
Wenzhou Key Lab of Advanced Energy Storage and Conversion, Zhejiang Province Key Lab of Leather Engineering, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325035, China.
Interfacial engineering is considered an effective strategy to improve the electrochemical water-splitting activity of catalysts by modulating the local electronic structure to expose more active sites. Therefore, we report a platinum-cobaltic oxide nanosheets (Pt/CoO NSs) with plentiful grain boundary as the efficient bifunctional electrocatalyst for water splitting. The Pt/CoO NSs exhibit a low overpotential of 55 and 201 mV at a current density of 10 mA cm for the hydrogen evolution reaction and oxygen evolution reaction in 1.
View Article and Find Full Text PDFNano Lett
December 2024
Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
Interparticle ligand exchange can occur during the formation of nanoparticle superlattices (NPSLs), affecting the symmetry of the NPSLs. Here, we report time-resolved small-angle neutron scattering (TR-SANS) measurements of the interparticle exchange kinetics of thiolate ligands among gold nanoparticles (AuNPs) at different temperatures. To track the ligand exchange among AuNPs, two groups of AuNPs were functionalized with hydrogenated and deuterated dodecanethiol, respectively, and then mixed in a solvent mixture of toluene and deuterated toluene for shell contrast.
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