نتایج جستجو برای: hydrogen desorption
تعداد نتایج: 165961 فیلتر نتایج به سال:
Electrochemical hydrogen and lithium absorptionrdesorption in Ti Ni Nb alloy in aqueous electrolytes
The electrochemical performance of a Ti Ni Nb electrode in different solutions has been studied. The Ti Ni Nb electrode can 46 45 9 46 45 9 Ž Ž . absorbrdesorb hydrogen in 3 M KOH aqueous and lithium in non-aqueous solution 1 M LiClO dissolved in a 50r50 vol.% vro 4 . mixture of ethylene carbonate and diethyl carbonate , respectively. It is assumed that lithium and hydrogen are incorporated in ...
Using thermal desorption mass spectrometry, we have shown unambiguously that the adsorption of atomic hydrogen on Si(100)-s2 3 1d leads to hydrogen pairing on silicon dimers at surface temperatures as low as 150 K and coverages as low as 0.2 monolayer. A detailed study of the adsorption kinetics shows a high probability of an abstraction reaction together with a coverage-dependent adsorption pr...
We address the changes in the electronic structure brought by the insertion of hydrogen into ThCo leading to the experimentally observed ThCoH4. Full geometry optimization positions the hydrogen in three sites stabilized in the expanded intermetallic matrix. From a Bader charge analysis, hydrogen is found to be in a narrow iono-covalent (∼−0.6) to covalent (∼−0.3) bonding which should enable si...
Nanoporous Pd (np-Pd) was prepared by co-sputtering Pd-Ni alloy films onto Si substrates, followed by chemical dealloying with sulfuric acid. X-ray diffractometry and chemical analysis were used to track the extent of dealloying. The np-Pd structure was changed from particle-like to sponge-like by diluting the sulfuric acid etchant. Using suitable precursor alloy composition and dealloying cond...
In this paper, the effects of dispersed 3~10 nm NbC precipitates on hydrogen diffusion in X80 pipeline steel were investigated by means of high resolution transmission electron microscopy (HRTEM), electrochemical hydrogen permeation, and thermal desorption spectroscopy (TDS). The relationship between hydrogen diffusion and temperature was determined for Nb-free X80 and 0.055 wt% Nb X80 steel. T...
We have studied the dehydrogenation properties of pure and Ti-doped Na3AlH6 surfaces using density functional theory. For the clean surface dehydrogenation is a multistep process, and involves the desorption of AlH4 complexes which disrupt the structure of the surface. By doping the system with Ti, we found that the segregation energy of Ti is negative, therefore favoring localization of the im...
the hydrogenation characterizations of the hydrogen storage alloy mmni4.22co0.48mn0.15al0.15 (mm= mischmetal), and the effect of hydrogenation/dehydrogenation (h/d) cycling on its structural and morphological properties are investigated. the results indicate that after several h/d cycles the alloy was pulverized into fine particles, but it kept its hexagonal cacu5-type structure. the pressure-c...
While the small sticking coefficient for molecular hydrogen on the Si(001) surface apparently requires a large energy barrier of adsorption, no such barrier is observed in desorption experiments. We have calculated the potential-energy surface of an H 2 molecule in front of a Si(001) surface. If we relax the Si substrate, we find an optimum desorption path with a low (< ∼ 0.3 eV) ad-sorption en...
A novel catalyst based on g-C3N4/activated carbon was prepared by adding CuCl2. The catalytic performance of the as-prepared catalyst was investigated in the acetylene hydrochlorination reaction. X-ray photoelectron spectroscopy, temperature programmed desorption, low temperature N2 adsorption/desorption (Brunauer–Emmett–Teller), and thermal gravity analysis showed that Cu-g-C3N4/AC significant...
5-Methoxysalicylic acid (MSA) is demonstrated to be a useful matrix for matrix-assisted laser desorption/ionization time-of-flight (TOF) mass spectrometry of oligonucleotides, when desorption/ionization without fragmentation is desired. When MSA is combined with the additive spermine, the need for desalting is reduced. The MSA/spermine matrix yields linear TOF mass spectra with improved resolut...
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