This could be some good news, but...
Generating and storing renewable energy, such as solar or wind power, is a key barrier to a clean-energy economy.
Basically, you have a cell that with sunlight will produce oxygen and hydrogen. You can do that today efficiently with many different technology like we see below (source)
So the question is, can this new technology match what we already can do?
- titanium dioxide
- gallium arsenide
- Plastic (oil from fossil fuel)
All those need to be mined, extracted, processed with energy mostly from fossil fuels based technology.
Those cells will only work when the sun is shining. Can only convert 10% of sunlight and works for 40 hours... So, it's costly, inefficient and produce waste.
Quite typical of "Green" energy I would say.
Will this be able to compete with existing technology to produce hydrogen? Probably not without large subsidies.