Unclickbaiting the title:

Photosynthetic power sources would absorb CO2

or

Photosynthesis could generate electricity while absorbing CO2

(according to the article. Using "could and would" because it doesn't seem to have been built, only modeled/computed/predicted. The paper linked in https://news.ycombinator.com/item?id=40668458 does not mention the absorbing aspect if I'm skimming the conclusion right but maybe it's implied because plants are known to take carbon from the atmosphere?)