FuelCellsWorks

US scientists have used an inkjet printer to produce large numbers of photoelectrodes in search of the ideal material to split water molecules and release hydrogen.

Hydrogen is in demand as an alternative energy source and a cheap and efficient method of producing it is a desirable goal. Splitting water molecules using sunlight’s energy fits the bill but there is a need for effective photoelectrodes to do this. Some photoelectrodes, such as metal oxide semiconductors, have long-term stability in sunlight but are inefficient at energy conversion; others exhibit high energy conversion efficiencies but are unstable in sunlight. There is a need for materials with both properties and a fast method to find them.

Now, Nathan Lewis and co-workers at the California Institute of Technology, Pasadena, think that they may have found the solution. Lewis used combinatorial chemistry, which allows large numbers of compounds to be produced at once, to make approximately 200 potential photoelectrodes at a time. They mixed metal ion solutions and printed them into 200 wells on glass coated with tin oxide using an inkjet printer. They then heated the solutions on the glass to form mixed metal oxides. The team tested the oxides for their ability to absorb sunlight and convert it into energy in a high-throughput fashion.

This allows a large database of compounds and their properties to be built up quickly and, as Lewis explains, the data could be used to ‘guide exploration of additional sets of materials for desirable activity in photoelectrochemical solar-based water splitting.’

P. Davide Cozzoli, an expert in nanocrystalline semiconductors from the University of Salento, Lecce, Italy, believes this method will ultimately lead to ‘new photocatalytically active semiconductors for cost-effective production of alternative eco-friendly fuel molecules, thus overcoming the inherent limitations of materials available in nature.’

Elizabeth Davies

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