Topic: solar cells producing hydrogen direct

[piersdad]

Solar electrolysis converts sunlight into electricity to split water molecules, but until recently solar water splitting devices have proved woefully inefficient. Traditional solar panels, called photovoltaic cells, can be used to generate clean electricity. But this kind of solar cell by itself is impractical for producing hydrogen because an extra step is needed to deliver the electricity generated to the electrolyte.

Direct electrolysis of water is different. Using a photoelectrochemical (PEC) cell, sunlight strikes a special catalyst submerged in the electrolyte itself—in this case, water—eliminating the extra step of transporting the electricity to where it does the work. PEC cells may one day serve as the backbone of a national hydrogen production program. But despite record-breaking achievements in efficiency, the best cells developed so far work for only 240 hours before corroding to a halt. To meet Department of Energy goals for this technology, these cells must work for at least 10,000 hours.

Exactly why these solar cells corrode so quickly is the question researchers at SLAC are now addressing, thanks in part to the efforts of Schiros, a PhD student conducting dissertation research at SSRL. Schiros and colleagues, under the guidance of Stanford Professor Anders Nilsson, are using soft x-rays to look directly into these PEC cells and observe the electrical and chemical reactions occurring at the edge of where water and semiconductor meet. By tracking the corrosion of the semiconductor surfaces on the atomic level, Schiros's work could lead to longer lasting PEC cells.

"We've shown in the lab that we can efficiently produce hydrogen," said Schiros, "but we're a long way from making cells that are stable long enough to meet DOE goals. But by finding the right materials, we will be one step closer to a clean energy infrastructure fueled by a renewable source of hydrogen."

if these guys can crack this problem then there will be a lot of  other problems solvable.

my experiments with aluminium/air cells many years ago came up with similar problems and got very poor currents due to hydrogen build up on the plates.
their problem is corrosion from the hydrogen  being released from the cells which at the instant of release is very corrosive being atomic hydrogen ( the atom is very hungry and wants to combine with anything it can -- in simpler terms)



hydrogen  direct from solar power