Could UV lasers be used to split CO2 and H2O?

[jcap]

I was wondering whether intense UV light, tuned to the correct wavelength, could be used to split carbon dioxide and water molecules as a first step towards synthesizing liquid fuels.

 

[Bystander]

To what end?

 

[jcap]

To what end?

Well, to make hydrocarbon fuels efficiently using solar electricity rather than getting them out of the ground and adding to global warming.

 

[HAYAO]

I really don't know what the question is trying to say. Are you asking would a photochemical reaction of water and carbon dioxide lead to hydrocarbon fuels?

 

[Charles Link]

This question has come up previously on Physics Forums, I think about 6 months ago. Anyway, here is a "link" that the OP may find of interest: https://www.technologyreview.com/s/601641/a-big-leap-for-an-artificial-leaf/ It apparently is an area of much ongoing research.

 

[jcap]

I really don't know what the question is trying to say. Are you asking would a photochemical reaction of water and carbon dioxide lead to hydrocarbon fuels?

I'm asking whether uv light can be used to efficiently spit H20 and CO2 molecules. I understand that UV photons have roughly the same energy as covalent bonds so I thought it might be possible.

 

[Borek]

Just breaking a bond is only a smart part of the process, not necessarily the most important one. Even assuming you were able to split water into oxygen and hydrogen you get a mixture of two highly reactive gases being heated and excited by the UV radiation. Guess what will happen next.

 

[DrStupid]

Even assuming you were able to split water into oxygen and hydrogen you get a mixture of two highly reactive gases being heated and excited by the UV radiation. Guess what will happen next.

The OP is talking about the photolysis of water and carbon dioxide (and not just pure water). It is not as easy to guess what happens with a mixture of H2O, H2, O2, H, O, OH, CO2, CO and C. That would strongly depend on the conditions and the presence of catalysts.

 

[HAYAO]

I'm asking whether uv light can be used to efficiently spit H20 and CO2 molecules. I understand that UV photons have roughly the same energy as covalent bonds so I thought it might be possible.

Okay, then the answer is very unlikely.

Might want to rely on photocatalysts instead. There are several difficulties in using UV lights source including, but not limited to, 1) do we have a efficient UV light source? 2) How "intense" is the light source? 3) How dense are the H2O and CO2 molecules? 4) How efficient are the reactions itself? 5) How about the byproducts?
Given these question, would using UV light source overcome the disadvantages?