The effects of catalysis using vanadium as an additive (2 and 5 wt.%) in a high-energy ball mill on composite desorption properties were examined. The influence of microstructure on the dehydration temperature and hydrogen desorption kinetics was monitored. Morphological and microstructural studies of the synthesized sample were performed by X-ray diffraction (XRD), laser particle size distribution (PSD), and scanning electron microscopy (SEM) methods, while differential scanning calorimetry (DSC) determined thermal properties. To further access amorph species in the milling blend, the absorption spectra were obtained by FTIR-ATR analysis (Fourier transform infrared spectroscopy attenuated total reflection). The results show lower apparent activation energy (Eapp) and H desorption temperature are obtained for milling bland with 5 wt.% added vanadium. The best explanation of hydrogen desorption reaction shows the Avrami-Erofeev model for parameter n = 4. Since the obtained value of apparent activation energy is close to the Mg-H bond-breaking energy, one can conclude that breaking this bond would be the rate-limiting step of the process.
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http://dx.doi.org/10.3390/ma16155480 | 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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