Method for rapidly carrying out hydrogenation of a hydrogen storage material

Abstract

Disclosed is a method for rapidly carrying out a hydrogenation of a material capable of absorbing hydrogen. It was discovered that when a powder of a material capable of absorbing hydrogen is ground under a hydrogen pressure, not at room temperature but at a higher temperature (about 300° C. in the case of magnesium) and in the presence of a hydrogenation activator such as graphite and optionally a catalyst, it is possible to transform completely the powder of this material into a hydride. Such a transformation is achieved in a period of time less than 1 hour whereas the known methods call for periods of time as much as 10 times longer. This is an unexpected result which gives rise to a considerable reduction in the cost of manufacture of an hydride, particularly MgH 2 .

1 . A method for rapidly carry out a hydrogenation of a hydrogen storage material, comprising the step of subjecting said material to a mechanical grinding in the presence of a hydrogenation activator and under hydrogen pressure and a temperature higher than the room temperature.  
     
     
         2 . The method according to  claim 1 , wherein the hydrogen pressure is equal to or higher than 1 bar.  
     
     
         3 . The method according to  claim 2 , wherein the temperature is equal to or higher than 50° C.  
     
     
         4 . The method according to  claim 3 , wherein the mechanical grinding is carried out within an enclosure with a mechanical energy equal to or higher than 0.05 kW/liter.  
     
     
         5 . The method according to  claim 4 , wherein the hydrogenation activator is graphite.  
     
     
         6 . The method according to  claim 5 , wherein the graphite is used in an amount equal to or higher than 1% by weight.  
     
     
         7 . The method according to  claim 6 , wherein the graphite is used in an amount equal to or higher than 3% by weight.  
     
     
         8 . The method according to  claim 4 , wherein the hydrogenation activator is a hydrocarbon.  
     
     
         9 . The method according to  claim 4 , wherein the hydrogenation activator is selected from the group consisting of naphthalene, perylene, pentacene, adamantane, fullerene and vulcan.  
     
     
         10 . The method according to  claim 4 , wherein the material is magnesium.  
     
     
         11 . The method according to  claim 10 , wherein in that the hydrogen pressure is equal to about 4 bars and the temperature is equal to about 300° C.  
     
     
         12 . The method according to  claim 11 , wherein the hydrogenation activator is graphite and is used in an amount equal to or higher than 1% by weight.  
     
     
         13 . The method according to  claim 12 , wherein the mechanical grinding is carried out in the presence of vanadium as a catalyst.  
     
     
         14 . The method according to  claim 4 , wherein the mechanical grinding is carried out in the presence of a catalyst.  
     
     
         15 . The method according to  claim 14 , wherein the catalyst consists of vanadium and is present in an amount equal to or higher than 1% at.  
     
     
         16 . The method according to  claim 4 , wherein said material contains sodium and aluminum.  
     
     
         17 . A material for the storage, transportation and/or production of hydrogen said material containing a hydrogenation activator and having been subjected to a hydrogenation carried out by the method according to  claim 4 , with the proviso that when the activator is graphite, cyclohexane, tetrahydrofuran or anthracene, then the material is not selected from the group consisting of Mg, Mg—Ni, Mg—Ru, Mg—Pt, Mg—Pd, NaAlH 4  and Na 3 AlH 6 .  
     
     
         18 . The material according to  claim 16 , wherein the hydrogenation activator is a solid, liquid or gaseous hydrocarbon.