Cobalt catalyst advances water splitting process

Researchers at Cambridge University have produced hydrogen, H₂, from water using a catalyst under industrially relevant conditions.

Although H₂ cannot be used as a ‘direct’ substitute for gasoline or ethanol, it can be used as a fuel in combination with fuel cells.

It is currently produced from fossil fuels and creates the greenhouse gas CO₂ as a by-product. As a result it is neither renewable nor clean.

Researchers claim their process, which uses a cobalt catalyst, is a significant step to providing a truly green solution.

Very little progress was made so far with homogeneous catalyst systems that work in water and atmospheric O₂

One of the many problems that scientists face is finding an efficient and inexpensive catalyst that can function under real-world conditions: in water, under air and at room temperature.

Currently, highly efficient catalysts such as the noble metal platinum are too expensive and cheaper alternatives are typically inefficient.

Very little progress was made so far with homogeneous catalyst systems that work in water and atmospheric O₂.

Cambridge researchers found that a simple catalyst containing cobalt, a relatively inexpensive and abundant metal, operates as an active catalyst in pH neutral water and under atmospheric O₂.

Dr Reisner said: “Until now, no inexpensive molecular catalyst was known to evolve H₂efficiently in water and under aerobic conditions. However, such conditions are essential for use in developing green hydrogen as a future energy source under industrially relevant conditions.

“Our research has shown that inexpensive materials such as cobalt are suitable to fulfil this challenging requirement. Of course, many hurdles such as the rather poor stability of the catalyst remain to be addressed, but our finding provides a first step to produce ‘green hydrogen’ under relevant conditions.”

The results show that the catalyst works under air and the researchers are now working on a solar water splitting device, where a fuel H₂ and the by-product O₂ are produced simultaneously.