Energy from hydrogen

"Water is the coal of the future" wrote Jules Verne in his adventure story "The Mysterious Island" back in 1875. Today, hydrogen is regarded as a major source of energy. But how can hydrogen be produced in an environmentally friendly way and utilised on a large scale?

One answer to this question is water splitting with the help of sunlight, according to Prof Dr Thorsten Klüner from the Institute of Pure and Applied Chemistry. "The splitting of water into hydrogen and oxygen influenced by the sun could soon contribute to energy production on a large scale," says Klüner, who heads the "Theoretical Chemistry" working group. Hydrogen could then play an important role in the energy mix of the future.

Klüner is investigating the chemical processes that need to take place for sunlight to split water into hydrogen and oxygen in a separate project. "Quantum chemical and quantum dynamic studies on photocatalytic water splitting on titanium dioxide surfaces" is the title of the project, which is part of the recently launched nationwide priority programme of the German Research Foundation (DFG) "Regeneratively produced fuels through light-driven water splitting". The DFG is supporting Klüner's work with a total of 400,000 euros.

"The combustion of hydrogen releases huge amounts of energy," says Klüner, explaining the background to the project. And instead of environmentally or climate-damaging loads, as with other processes, only pure water is produced. "Light-driven water splitting - photocatalysis - could therefore be a promising way to produce hydrogen in an environmentally friendly way," explains Klüner.

The biggest hurdle so far: finding suitable material for splitting the water. Klüner is now using titanium oxide. "The mineral occurs naturally, so it no longer has to be extracted at great expense." It is also chemically very stable, non-toxic - and highly reactive.

Even if the right material has been found, the splitting of water on titanium dioxide surfaces has hardly been researched to date. "The basic elementary steps at the atomistic level are largely not understood," says Klüner. This is precisely where the "Theoretical Chemistry" working group comes in: It is investigating the mechanisms of water splitting by light on an atomic scale. This requires complex quantum chemical calculations that are unique in the world - and which scientists in Oldenburg can carry out precisely on the Oldenburg mainframe computer HERO and at the High Performance Computing Centre Stuttgart (HLRS).

State-of-the-art methods of quantum chemistry and quantum dynamics, local and national supercomputers: Klüner is confident that he will be able to use these tools to develop a new design of more efficient photocatalysts based on titanium dioxide. "With these photocatalysts, it should be possible to utilise light-driven water splitting commercially on a large scale in the foreseeable future."