We examined the catalytic effect of nanoparticle 3d-transition metals on hydrogen desorption (HD) properties of MgH(2) prepared by mechanical ball milling method. All the MgH(2) composites prepared by adding a small amount of nanoparticle Fe(nano), Co(nano), Ni(nano), and Cu(nano) metals and by ball milling for 2 h showed much better HD properties than the pure ball-milled MgH(2) itself. In particular, the 2 mol % Ni(nano)-doped MgH(2) composite prepared by soft milling for a short milling time of 15 min under a slow milling revolution speed of 200 rpm shows the most superior hydrogen storage properties: A large amount of hydrogen ( approximately 6.5 wt %) is desorbed in the temperature range from 150 to 250 degrees C at a heating rate of 5 degrees C/min under He gas flow with no partial pressure of hydrogen. The EDX micrographs corresponding to Mg and Ni elemental profiles indicated that nanoparticle Ni metals as catalyst homogeneously dispersed on the surface of MgH(2). In addition, it was confirmed that the product revealed good reversible hydriding/dehydriding cycles even at 150 degrees C. The hydrogen desorption kinetics of catalyzed and noncatalyzed MgH(2) could be understood by a modified first-order reaction model, in which the surface condition was taken into account.

Catalytic effect of nanoparticle 3d-transition metals on hydrogen storage properties in magnesium hydride MgH2 prepared by mechanical milling.

https://ir.lib.hiroshima-u.ac.jp/files/public/2/20049/2014101613480317296/JAllCompd_365_1-2_271.pdf

Lithium nitride for reversible hydrogen storage

Tailoring magnesium based materials for hydrogen storage through synthesis: Current state of the art

A catalyst for purifying exhaust gases exhibits not only effective purifying characteristics even in a low temperature range such as immediately after an engine starts but also high exhaust gas purifying ability. In the catalyst for purifying exhaust gases of a first aspect of the invention, HC adsorbed at low temperature are released at high temperature and the released HC are purified by a catalyst metal. This catalyst for purifying exhaust gases has an excellent advantage in purifying HC at low temperature as well as excellent exhaust gas purifying ability.

Catalyst for purifying exhaust gases

Tuning kinetics and thermodynamics of hydrogen storage in light metal element based systems – A review of recent progress

In the exhaust gas purifying catalyst (3), palladium is contained as a catalytic component and cerium oxide and (Ce, Pr) compound oxide is contained as a promoter. Now, the weight ratio of cerium oxide to (Ce, Pr) compound oxide is set between 9/1 and 7/3, and the ratio of praseodymium to cerium in the (Ce, Pr) compound oxide is set between 3 mol % and 50 mol %. In this way, because in this exhaust gas purifying catalyst (3), palladium with high low-temperature activity is used for a catalytic component, the exhaust gas purifying performance at low temperature is improved. And because cerium oxide and (Ce, Pr) compound oxide improves catalytic activity of palladium at high temperature, the exhaust gas purifying performance at high temperature, in particular, NOx purifying performance, is improved.

Catalyst for cleaning exhaust gas

A high-strength steel sheet includes, by mass %, C: 0.03% to 0.30%, Si: 0.08% to 2.1%, Mn: 0.5% to 4.0%, P: 0.05% or less, S: 0.0001% to 0.1%, N: 0.01% or less, acid-soluble Al: more than 0.004% and less than or equal to 2.0%, acid-soluble Ti: 0.0001% to 0.20%, at least one selected from Ce and La: 0.001% to 0.04% in total, and a balance of iron and inevitable impurities, in which [Ce], [La], [acid-soluble Al], and [S] satisfy 0.02≦([Ce]+[La])/[acid-soluble Al]<0.25, and 0.4≦([Ce]+[La])/[S]≦50 in a case in which the mass percentages of Ce, La, acid-soluble Al, and S are defined to be [Ce], [La], [acid-soluble Al], and [S], respectively, and a microstructure includes 1% to 50% of martensite in terms of an area ratio.

High-strength steel sheet and method for producing same

In this paper, we review our recent results on hydrogen storage, structural and optical properties in multi-layered Pd/Mg thin films. The thin films were prepared using a RF associated magnetron sputtering method, in which the structure in Mg layer was controlled into columnarlike textures with several tens nanometer in diameter by optimizing the sputtering conditions. The results obtained indicate that hydrogen of ∼ 5 mass% absorbs at 373 K in Mg under a hydrogen pressure of 0.1 MPa in multi-layered Pd/Mg films and the hydrogen desorbs at 360 K in vacuum. Such excellent hydrogen storage properties are explained by cooperative phenomena that hydrogen displays in nano-composite interface boundary regions between the Pd and Mg films. In addition, we experimentally confirmed at the first time that the rare earth and nickel free two-layered Pd/Mg film displayed optical transparency upon hydrogenation.

Remarkable Hydrogen Storage, Structural and Optical Properties in Multi-layered Pd/Mg Thin Films

We have developed new composite materials for hydrogen storage containing ZrFe1.4Cr0.6 or TiMn1.5 as a storage material and magnesium as a binder. The influences of composition, compacting pressure and heat treatment on hydrogen capacity, kinetics and cyclic durability of the composite pellets were examined by repeating absorption-desorption cycles. The pellets obtained by sintering the mixtures at 773 K for 20–40 h absorb hydrogen readily and very quickly under a hydrogen pressure of less than 1 MPa without any activation treatment, and exhibit no disintegration after 1000 hydriding—dehydriding cycles. Observations of the microstructure and distribution of metals and oxygen atoms in the composites, using scanning electron microscopy, electron probe microanalysis and electron spectroscopy for chemical analysis, indicate that the heat treatment at 773 K not only promotes the so-called magnesium reduction and makes the surface of the hydride clean, but it also helps to form a new thin composite phase on the boundary between the original hydride and unreacting magnesium metal which acts as a binder, keeping the pellet intact upon hydrogenation.

New composite materials for hydrogen storage using magnesium as a binder

A catalyst for lowering NOx concentration in an exhaust gas is disposed in an exhaust gas passage of an engine. The catalyst composed of a catalyst layer formed on a substrate. A NOx absorber that absorbs NOx when an oxygen concentration in the exhaust gas is high and releases NOx when the oxygen concentration drops, and a precious metal for reducing NOx are supported on a support material as catalyst components, and the NOx absorber includes Ba, K, Sr, and Mg. By lowering the oxygen concentration in the exhaust gas and raising a temperature of the NOx absorber when sulfur component is absorbed excessively in the NOx absorber, it is possible to regenerate the catalyst from the S poisoning.

Device for purifying exhaust gas, method for purifying exhaust gas, catalyst for purifying exhaust gas, and method for manufacturing exhaust gas purifying catalyst

Kenichi Yamamoto

Papers

Catalyst for cleaning exhaust gas

High-strength steel sheet and method for producing same

Remarkable Hydrogen Storage, Structural and Optical Properties in Multi-layered Pd/Mg Thin Films

New composite materials for hydrogen storage using magnesium as a binder

Device for purifying exhaust gas, method for purifying exhaust gas, catalyst for purifying exhaust gas, and method for manufacturing exhaust gas purifying catalyst