If you can beat the HB and Ostwald processes, I say go for it. I think the idea behind carbon capture from serious people is: 1. That it should be solar powered / low energy 2. Catalyst cheap as dirt, so that 3. CO2 in the air is free, so you'd basically have the plant start up costs and then the rest is free money. Also envy of the plants for making it look easy.

Anybody saying it would make a dent on the global CO2 consumption is just spouting grant proposal talk, for the entropic reasons everyone else is talking about on this thread, or else is a crazy geoengineering nut.

That being said, if you dig into it, most groups that publish papers on the subject do it as an interesting sideline / something to grab some low hanging attention. It's really just checked out as a side effect of other things, like being able to functionalize hard to move chemical groups.

One of my Fe compounds could capture CO2 gas and convert it into oxalic acid ( H2O + 2CO2 =cat=> H2(CO2)2 + 1/2O2 ) ... almost a whole 50 cycles before it got poisoned by its own O2 production (the compound burst into flames in air, btw). But it could also functionalize one of the lowest energy N bonds known, and in a selective fashion. It was floated as a means for a two step synthesis of some kidney drug, but ... the bursting into flame thing.