Fun idea - very back of the envelope math is if you could convert energy into strictly breaking CO2 bonds, the amount of energy it takes is 805 kJ/mol (from Google). WolframAlpha says this is roughly the caloric content of a biscuit, or 30 min of sports [1]. This would then separate 22.4 L or one mole of pure CO2.

There are approximately 1E20 moles of CO2 in the atmosphere (very rough math)[2,3]. This could take a while, especially considering efficiency would probably be 10% of this idealized system. However, this filtering idea isn't bad, I don't know of any filter like this for splitting CO2, but something is almost certainly being worked on for just general sequestration of CO2 from other atmospheric gasses.

[1] https://www.wolframalpha.com/input/?i=805+kJ

[2] http://www.wolframalpha.com/input/?i=(5.148E18+kg)%2Fmolar+m...

[3] https://micpohling.wordpress.com/2007/03/30/math-how-much-co...