The mechanism of recombinative desorption of hydrogen from a Ru(0001) surface induced by femtosecond-laser excitation has been investigated and compared to thermally initiated desorption. For the laser-driven process, it is shown that hot substrate electrons mediate the reaction within a few hundred femtoseconds resulting in a huge isotope effect between H2 and D2 in the desorption yield. In mi...

The most important unsolved problem for the introduction of the Hydrogen Economy is efficient and safe storage of hydrogen. Alanates, compounds based on the AlH4 unit, are among the most promising metal hydrides for reversible hydrogen storage. The storage capacity is large, e.g. NaAlH4 can release 5.6 wt% hydrogen below 200 C. Work during the last years has revealed that Ti additives improve t...

We proposed a new solid state material for hydrogen storage, which consists of a combination of both transition and alkaline earth metal atoms decorating a boron-doped graphene surface. Hydrogen adsorption and desorption on this material was investigated using density functional theory calculations. We find that the diffusion barriers for H atom migration and desorption energies are lower than ...

The adsorption and hydrogenation of methyl iodide is studied on clean and hydrogen-covered Pd(1 1 1) using reflection–adsorption infrared spectroscopy (RAIRS) and temperature-programmed desorption. Molecular methyl iodide desorbs from clean Pd(1 1 1) at 229 K and hydrogen desorbs at 360 K. Methyl groups hydrogenate in two states at 191 and 304 K for large methyl iodide exposures where RAIRS dat...

Novel approaches to efficient ammonia synthesis at an ambient pressure are actively sought out so as to reduce the cost of ammonia production and to allow for compact production facilities. It is accepted that the key is the development of a high-performance catalyst that significantly enhances dissociation of the nitrogen-nitrogen triple bond, which is generally considered a rate-determining s...

Kinetics of hydrogen absorption and desorption reactions was investigated on the MgH2 composite doped with 1 mol% Nb2O5 as a catalyst by ballmilling. The composite after dehydrogenation at 200 °C absorbed gaseous hydrogen of ~ 4.5 mass% even at room temperature under lower pressure than 1 MPa within 15 sec and finally its capacity reached more than 5 mass%. On the other hand, the catalyzed MgH2...

Palladium has a face-centered-cubic sublattice. Hydrogen atoms partially fill the octahedral holes to form PdH,. The fraction of interstitial sites occupied is dependent on the plating conditions, temperature and the partial pressure of hydrogen, etc. Although hydrogen atoms only occupy the interstitial’ sites, the sublattice of metal atoms in the PdH, is larger and simply an expansion of the p...

Oxidation of amorphous silicon (a-Si) nanoparticles grown by plasma-enhanced chemical vapor deposition were investigated. Their hydrogen content has a great influence on the oxidation rate at low temperature. When the mass gain is recorded during a heating ramp in dry air, an oxidation process at low temperature is identified with an onset around 250 °C. This temperature onset is similar to tha...

After a concise review of the analytical models available for the interpretation of thermal desorption rates for hydrogen effusion from steel, a numerical method that incorporates the essence of local equilibrium and detrapping kinetics has been implemented to account for the real complexity of practical experiments. For example, the model permits the treatment of multiple kinds of traps, uses ...