Hydrogen generation method

Abstract

The invention provides a hydrogen generation method comprising the step of bringing, in the presence of water, ammonia borane represented by the chemical formula: NH3BH3 into contact with (1) a catalyst comprising as an active ingredient at least one member selected from the group consisting of metal catalysts and metal compound catalysts; (2) a solid acid; or (3) carbon dioxide. The method of the invention can generate hydrogen gas for use as fuel for fuel cells, etc., under controllable conditions without heating a starting material at high-temperature, and moreover can efficiently generate hydrogen gas at low cost.

Description

BACKGROUND OF THE INVENTION [0001] (1) Field of the Invention [0002] The present invention relates to a hydrogen generation method. [0003] (2) Description of the Related Art [0004] Various methods for generating hydrogen gas are currently known, and specific examples thereof include the electrolysis of water; the reaction between metal and acid; the reaction of water with metal hydride; the reformation of methyl alcohol or natural gas with steam; the release of hydrogen from hydrogen storage materials, such as hydrogen storage metal alloys, activated carbon, carbon nanotubes and lithium-nitrides, etc. However, these methods are disadvantageous in that much energy is required to generate hydrogen, the amount of hydrogen generated is small relative to the amount of starting materials used, large-scale equipment is required, etc. Due to such disadvantages, although these methods are applicable to the hydrogen generation in industrial scale or in laboratory scale, these methods are not ...

AI Technical Summary

Benefits of technology

[0008] The invention was made in view of the prior-art problems, and a principal object of the invention is to provide a novel hydrogen generation method capable of efficiently generating hydrogen gas for use as fuel for fuel cells, etc., under controllable conditions without heating a starting material at high-temperature.

[0009] The inventors carried out various studies focusing on ammonia borane represented by the chemical formula: NH3BH3 as a hydrogen source material and found the following properties of ammonia borane. That is, although ammonia borane is soluble in water to form a highly stable aqueous solution, the aqueous solution generates hydrogen gas when it is brought into contact with a specific substance. The amount of hydrogen to be generated and the generation rate of hydrogen from the aqueous solution can be easily controlled. The present invention was accomplished based on these findings.

Problems solved by technology

However, these methods are disadvantageous in that much energy is required to generate hydrogen, the amount of hydrogen generated is small relative to the amount of starting materials used, large-scale equipment is required, etc.

Due to such disadvantages, although these methods are applicable to the hydrogen generation in industrial scale or in laboratory scale, these methods are not suitable for use in supplying hydrogen to fuel cells for automobiles; portable fuel cells for cellular phones, personal computers, etc. and like fuel cells in which a required amount of hydrogen needs to be continuously supplied and a system should be small.

Also in this respect, such compounds are not suitable for use as hydrogen supply sources for the above-described fuel cells.

However, since ammonia borane is heated at a high temperature for thermal decomposition in the method, a large quantity of energy is needed and control of the reaction is difficult (V. Sit, et al., Thermochimica Acta, 113 (1987) 379; A.T-Raissi, Proceedings of the 2002 US DOE Hydrogen Program Review).

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