How Does Metal Hydride Formation Occur?

[mess1n]

I'm very confused about how metal hydrides form. I'm looking at PCI plots and I see what's happening, but I have no idea why it is. For instance:

"Molecular hydrogen is dissociated at the surface before absorption; two H atoms recombine to H₂ in the desorption process."

Why does this happen?

Also, I've attached a PCI plot. Can anyone explain why the concentration suddenly increases at certain pressures?

I've searched so many books and internet resources to try and find an explanation for these processes, to no avail, please help! :(


Andrew

 

[mess1n]

Sorry to bump this, but I'm hoping someone sees it who will be able to help. Is this question in the right section?

 

[Astronuc]

There is a theory of autocatalytic dissociation of hydrogen in metals.
http://www.springerlink.com/content/f602850hk808h357/

And there is this
Hydrogen dissociation on metal surfaces – a model system for reactions on surfaces
Applied Physics A: Materials Science & Processing
Volume 67, Number 6, 627-635, DOI: 10.1007/s003390050834
A. Gross

Clearly to form hydrides, the proton has to diffuse through the metallic grains/crystal structure. The solubility of hydrogen in a metal is temperature dependent.

 

[mess1n]

Thanks so much for the reply, I'll read through those articles now.