Carbon nanotube catalysts for converting CO2 to CO

Converting solar or wind into carbon-based fossil fuels might seem anything but green, but when you start with carbon dioxide - which can be dragged out of the air - it's as green as it gets. The technology that makes it economically feasible isn't available yet, but a recently published paper presents nice step forward in the effort to not just sequester CO2, but turn it into a useful fuel that is part of a carbon-neutral future.