John Timmer has an interesting article on Ars Technica. Though the headline is about methane production, it appears to be easier to make carbon monoxide, which might be the way to go on, e.g., Mars.Here's the link to the underlying paper in Nature.
One thing that's clear is that this is an utterly abysmal way of using light energy, with a quantum yield of about 0.18 percent, meaning that only a tiny fraction of the photons supplied are used as energy to produce methane. By contrast, a lot of catalysts that split water using light produce hydrogen with a quantum efficiency over five percent.
Correct link: https://arstechnica.co.uk/science/2017/07/cheap-catalyst-takes-sunlight-and-carbon-dioxide-makes-methane/