How to split a water molecule

Apr 18, 2010
Figure 1: STM image of ultrathin MgO film on Ag(100) surface.

(PhysOrg.com) -- A research team at RIKEN, Japan’s flagship research organization has succeeded for the first time in selectively controlling for reaction products in the dissociation of a single water molecule on an ultrathin film. The reaction, described in the April 19th issue of Nature Materials, opens the door to the creation of novel functional catalysts and applications in clean energy production.

In recent years, the knowledge that materials exhibit novel properties at the nano-scale has driven a search for functional nano-materials with useful applications. Among these, ultrathin films have attracted attention for their application in reaction catalysis, yet mechanisms underlying this catalytic role have remained unclear.

Using a scanning tunneling microscope (STM) at ultra-low temperatures, the research team explored the dynamics of single water molecules interacting with a film of magnesium oxide (MgO) several atoms in thickness (Figure 1).

They discovered that by injecting tunnelling electrons into water molecules on the MgO surface (Figure 2), they could select between dissociation pathways: excitation of the molecule’s vibrational states induced dissociation into hydroxyl (H + OH) (Figure 3 (a) and (b)), whereas excitation of its electronic states induced dissociation into atomic oxygen (O) (Figure 3 (c) and (d)).

Figure 2: STM image of isolated water molecules adsorbed on ultrathin MgO surface.

STM images of water molecule before (a) and after (b) dissociation into OH, and before (c) and after (d) dissociation into O.

The controlled dissociation of water molecules via selected reaction pathways presents unique opportunities in targeted catalysis, particularly in the production of hydrogen, a potential source of . While advancing our understanding of the dynamics of , the discovery also sets the stage for applications in the catalysis of more complex systems on insulating films.

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User comments : 8

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Auxon
not rated yet Apr 18, 2010
So sound and light both work together in photosynthesis.
mesplin
5 / 5 (2) Apr 18, 2010
ummm.... no. I don't think it mentioned anything about sound in the article, nor photosynthesis. They just split a water molecule.
Mercury_01
5 / 5 (1) Apr 19, 2010
Needed: one tiny chisel.
thermodynamics
5 / 5 (1) Apr 19, 2010
Auxon: I think you are confusing the vibrational quantum modes with sound. This has to do with the way that the molecules vibrate and is more related to electromagnetism than sound. They are quantum states into which the molecule can be excited. My understanding is that the vibrational states are along the bonds from H to O. They also excited electrons into higher orbitals and those seemed to release the O atom. The idea that this had to be done on the MgO catalyst is interesting.
Tan0r5
1 / 5 (1) Apr 20, 2010
Really brilliant using water one of the most limited resources for fuel! Same for food crops for ethanol. Instead use plastics and wastes to liquid to ethanol!
Auxon
not rated yet Apr 21, 2010
Auxon: I think you are confusing the vibrational quantum modes with sound. This has to do with the way that the molecules vibrate and is more related to electromagnetism than sound. They are quantum states into which the molecule can be excited. My understanding is that the vibrational states are along the bonds from H to O. They also excited electrons into higher orbitals and those seemed to release the O atom. The idea that this had to be done on the MgO catalyst is interesting.


Thanks. :)
jcrow
not rated yet Apr 29, 2010
Tan0r5
>Water
>one of the most limited resources
hopper
1 / 5 (1) May 05, 2010
Consider that Kansius was able to use a radio wave at frequency 13.5 or the Nuclear Magnetic Resonance of oxygen to dissociate H20 water in the presence of Na+ magnesium and Cl- ion or salt water. Likely the Na+ contributed a lot of heat that it absorbed from the radio waves while the 13.5 frequency rattled the oxygen out of its Hydrogen bonds. So what would happen if you did the Kansius reaction in the presence of the MgO catalyst. Would it make it more efficient?

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