A few weeks ago I wrote a news story about some work done by Dan Nocera at MIT. He's managed to make a very simple catalyst that can generate oxygen directly from water - so helping those people trying to mimic photosynthesis and save the world's energy crisis.

At the time Nocera wasn't sure what the mechanism was for the formation of the cobalt catalyst. In today's talk he confirmed what he had thought then - that the cobalt gets oxidised all the way to its +4 oxidation state. He was also very confident in the technology he is developing. "I guarantee in under five years you'll see this," he said. Companies are coming out of the woodwork, he says, to develop a functioning, practical system.

Other big claims he made were that in a system based on his catalyst cuold produce enough fuel to run a typical house for a day in just two and a half hours. This is big talk, Dan, I look forward to it becoming reality.