Lots of interesting details in the article this time

1. The scientists created a process for converting CO2 into carbon monoxide (at least that's what is stated). Wierd headline
2. There already were processes that reduced CO2 to carbon monoxide, this one replaces certain consumable organic compounds with a material that is not consumed. So it's cleaner and cheaper
3. The material is actually the star here. It stores electrons when exposed to light, and this helps reduce the CO2 in the processing steps. The material also works with natural sunlight so that's neat

If you don't know much about chemistry, "reducing" a compound is when you either

1. Add electrons
2. Loose protons
3. Add hydrogen
4. Remove Oxygen

If you're wondering what's up with hydrogen and oxygen, just know that hydrogen is the least "electronegative" of the common elements. It's basically the baby other elements can steal ~~candy~~ electrons from. So adding hydrogen gives extra electrons to other parts of the compound. Oxygen meanwhile is like a gangster for electrons. It steals them from everyone else (except flourine*), so getting rid of it the same as adding electrons.

*florine is the electron IRS.

If you are astute, you might notice that reductions are the exact opposite of oxidation (the latter of which consists of adding oxygen). I'm pretty sure most reductions need for you to add energy, which most oxidations release energy. There's other factors to it, but that's a good rule of thumb.

Also the reason we talk of adding of subtracting electrons is cause of acid and base chemistry. It's relevant there.