The headline is "solar-driven water splitting", but they do this by building an photovoltaic cell and connecting it to an electrolyser, just like everyone alrea

The headline is "solar-driven water splitting", but they do this by building an photovoltaic cell and connecting it to an electrolyser, just like everyone already does. Moreover, the innovation here is that neither the solar cell nor the electrolyser require rare elements. As they say: > Sustainable water electrolysis requires that the anode and cathode catalysts are noble metal free and contain small amounts of other metals in order to lower system costs and facilitate recycling. As for efficiency: > The measured [solar-to-hydrogen] efficiency is improved compared to all previous electrolyzers driven by low-cost [perovskite solar cells] that used solely Earth-abundant electrocatalysts but lower compared to the highest performing perovskite/Si tandem devices that uses noble metal electrocatalysts, which reached an initial efficiency of 17% [solar-to-hydrogen]. So this setup is less efficient than what we already have. But it doesn't require rare elements.