London, Sep 26 – In the race to optimize solar energy’s performance, scientists have used earth-abundant materials to harvest hydrogen fuel from the sun’s energy.
Their device converts into hydrogen 12.3 percent of the energy diffused by the sun on perovskite absorbers – a compound that can be obtained in the laboratory from materials such as those used in conventional car batteries.
This eliminates the need for rare-earth metals in the production of usable hydrogen fuel.
Both the perovskite used in the cells and the nickel and iron catalysts making up the electrodes require resources that are abundant on Earth and that are also cheap, explained Jingshan Luo, post-doctoral student in the team of lead researcher Michael Gratzel at the Swiss Federal Institute of Technology in Lausanne.
Our electrodes work just as well as the expensive platinum-based models customarily used, Gratzel said.
The conversion of solar energy into hydrogen makes its storage possible which addresses one of the biggest disadvantages faced by renewable electricity.
Once you have hydrogen, you store it in a bottle and you can do with it whatever you want to, whenever you want, Gratzel noted.
Such a gas can indeed be burned – in a boiler or engine – releasing only water vapour.
It can also pass into a fuel cell to generate electricity on demand.
And the 12.3 percent conversion efficiency achieved will soon get even higher, Gratzel added.
The paper appeared in the journal Science.