A new study at Uppsala University in Sweden has developed a coating material for semiconductors which enables fuel production to become more sustainable.
The ‘Enhancing photovoltages at p-type semiconductors through a redox-active metal-organic framework surface coating’ study, published in the Nature Communications journal, investigated the potential for sustainable production of hydrogen and methanol, to be used in fuel cells and as raw materials in chemical manufacturing. While hydrogen gas and methanol are currently primarily extracted from non-renewable fossil fuel sources, such as natural gas and oil, increased attention is now being paid to the possibilities offered by more environmentally sound processes whereby key fuel components can be produced by applying electrical voltage to water and carbon dioxide.
Researchers working on the study found they could reduce the voltage expended in the process by supplementing the electrical current with solar energy, deploying semiconductors of the same type used in solar cells to harvest the sunlight. In streamlining this process, the researchers developed a new coating material for the semiconductors which extracts electrons from the semiconductor when exposed to sunlight. These electrons can then be used for fuel-forming reactions.
The new semiconductor coating is a ‘metal-organic framework’, a three-dimensional network composed of individual organic molecules which are held together at a sub-nanometre level by minuscule threads of metal. The molecules capture the electrons generated by the sunlight and remove them from the surface of the semiconductor, averting the risk of undesired chemical reactions which could cause short-circuits within the system. Practical testing indicated that the semiconductor coating was able to ‘greatly’ reduce the voltage which was needed to extract electrons from the semiconductor.
Sascha Ott, Professor at Uppsala University’s Department of Chemistry, said: “We’ve moved a step closer to our goal of producing the fuel of the future from sunlight. Our results suggest that the innovative coatings can be used to improve semiconductor performance, leading to more energy-efficient generation of fuels with lower electrical input requirements.”