Harvard University researchers say they’ve created a half-chemical, half-biological system to generate liquid fuel, using air, water, and sunlight. As if that weren’t enough, it takes climate-changing carbon dioxide out of the atmosphere in the process.A study published on Thursday in the journal Science advances research led by Daniel Nocera, a professor of energy at Harvard who has spent years trying to best nature’s original workhorse technology—photosynthesis. Nocera has been developing what he calls an…