This seems to be a third system for producing solar hydrogen.

"A manganese cluster is central to a plant's ability to use water, carbon dioxide and sunlight to make carbohydrates and oxygen. Man-made mimics of this cluster were developed by Professor Charles Dismukes some time ago, and we've taken it a step further, harnessing the ability of these molecules to convert water into its component elements, oxygen and hydrogen," Professor Spiccia said.

"The breakthrough came when we coated a proton conductor, called Nafion, onto an anode to form a polymer membrane just a few micrometres thick, which acts as a host for the manganese clusters."

"Normally insoluble in water, when we bound the catalyst within the pores of the Nafion membrane, it was stabilised against decomposition and, importantly, water could reach the catalyst where it was oxidised on exposure to light."

This process of "oxidizing" water generates protons and electrons, which can be converted into hydrogen gas instead of carbohydrates as in plants. . .

Professor Spiccia said the efficiency of the system needed to be improved, but this breakthrough had huge potential.

The other systems noted recently had some similarities but focused on either cobalt or metal hydride rather than manganese. There seems to be a lot of ways to split water with sunlight to get hydrogen and/or oxygen.