MIT’s ‘Artificial leaf’ makes fuel from sunlight

The one bit that was sort of unconvincing was when he argued that if we create an exponentially growing photovoltaic industry it will (implication: indefinitely) take more energy to build than it provides. But it’s silly to assume the exponential growth to be unbounded: the whole idea is that once we build enough capacity, we can stop making more of the things and after a few years we get energy coming out without so much further (energy/money) investment. He made it sound like building photovoltaics at scale would be overall detrimental.

Other than that though, really excellent introductory background to put papers like this current one in context.

Pure O2 or H2 at atmospheric pressure isn't that useful. For example, it is very hard to use atmospheric pressure H2 to run an internal combustion engine.

It's easier to run an external combustion engine with atmospheric pressure H2, but said engine will have to be right on top of the H2 generator and since the engine needs a cooling source and the H2 generator requires sunlight, you may have enough of a temperature differential to run a heat engine directly, without the H2 intermediary.

The previous news had early versions of the device that used only a single junction PV. Thus, some external potential had to be applied for catalysis. Also, the device only had the oxygen evolving catalyst and relied on a buffer solution to supply the H+ ions. Therefore, the earlier versions of the device could not split water by itself when dropped into water.

This new device can.

http://2011.igem.org/Team:KULeuven

http://2011.igem.org/Team:KULeuven/Project

looking a bit further into the future, you might have a variant of this device produce petroleum or similar fuel for your car, with an added bonus of reducing the amount of carbon in the atmosphere.