Research Fellows Directory
Dr Andrew Ashley
Imperial College London
Humans are reliant upon hydrocarbon fossil fuels for their energy needs and demand is projected to double by 2050, yet fossil fuels are a finite resource and subject to fluctuating prices and supply concerns. Combustion of these also releases carbon dioxide (CO2), a major contributor to global warming.
A sustainable alternative is the storage of energy in the chemical bonds of hydrogen (H2) through the solar-splitting of abundant water (H2O). Unfortunately, H2 is a gas and has major storage problems for transportation, which relies on energy-dense liquid fuels. A solution is to use solar-derived H2 to convert atmospheric CO2 into liquid hydrocarbon fuels; because CO2 is used in their manufacture the fuel is overall carbon-neutral, and is known as ‘artificial photosynthesis’. The security of a dependable and carbon-neutral energy source would be a commercially attractive investment to oil-dependent industries. Success will not only generate academic interest, but the beneficial impacts will be felt by society across the world. Population rises will also apply pressure on food resources – this can be addressed through greater use of fertilisers to enhance agricultural yields. Currently, these are produced from ammonia, which is made from the energy-intensive reaction of nitrogen (N2) and H2, consuming ca. 2% of the global energy supply; energy-efficient ammonia synthesis is hence desirable.
Direct reaction of CO2/N2 and H2 does not occur due to the strong bonds holding the molecules together; to promote this a catalyst (which weakens bonds and drive the reactions forward) is required. This research proposal adopts a new approach to catalyst systems capable of both transformations using two catalysts in synergy: one makes H2 reactive, whereas another specifically binds CO2 or N2 molecules, rendering them susceptible to reaction with H2. Importantly the catalysts can be easily modified and their performance tuned, leading to more efficient and sustainable chemistry.
Interests and expertise (Subject groups)