Spectroscopy-driven design of an efficient photocatalyst for CO2 reduction (Ext.)

This is an extension of the original Fellowship "Spectroscopy-driven design of an efficient photocatalyst for CO2 reduction"

There is sufficient solar energy incident on the UK to provide for all of our energy needs. However the insolation level varies hugely both within a day and on a seasonal level. For any energy technology to be viable it is essential that it is reliable. A route to overcoming the intermittency of supply issue is to use the solar energy to drive the production of a chemical fuel which can be stored and transported to be available when and where it is needed. Sustainable carbon-based solar fuels and feedstocks (e.g. CH4, CH3OH, CO) can be produced by the coupling of light driven water oxidation to the reduction of CO2. This is an exciting prospect but to realise the goal of low carbon-intensity fuel economy breakthroughs are required for both fuel generation and utilisation systems. Current materials for CO2 reduction and water oxidation do not achieve the required level of efficiency and stability at a viable cost. Similarly the most promising clean technologies for electricity generation on demand from carbon fuels, fuel cells, often suffer from relatively low efficiencies and intolerances to impurities in the fuel feed.

The original fellowship has been highly successful in delivering new low-cost catalysts that can either be driven directly by sunlight (photocatalysts) or indirectly using electrical energy (which could in principle come from a PV panel) to reduce CO2 to CO, an important liquid fuel precursor. Part of the original fellowship developed new capabilities within the UK for a highly sensitive surface sensitive spectroscopy, IR-Vis Sum Frequency Generation Spectroscopy. This experiment has been used to identify with an incredible level of detail the mechanisms of catalysts at surfaces. These, and our wider spectroscopic studies, have been critical in guiding our own catalyst design programme. But the need for mechanistic insights extends beyond our own synthetic programme. A lack of understanding of the mechanisms of catalysis occurring on the surface of electrodes and photoelectrodes is a limiting factor for the entire field preventing the rational development of new materials. Therefore our spectroscopy driven programme will be expanded to address both the crucial reactions of fuel generation (water oxidation and CO2 reduction) as well as to fuel utilisation chemistry, through the study of state of the art metal-oxide fuel cells.

The project is ambitious, aiming not just to provide the first identification of all key intermediates during water oxidation on the most commonly studied photoelectrode (hematite), but also to explore how secondary interactions with water and electrolyte salts control the activity. A similar level of mechanistic detail is also sought from leading CO2 reduction catalysts and fuel cell electrodes. This level of mechanistic detail that we aim to deliver could be transformative to our own, collaborators and the wider communities programmes of material development. The delivery of scalable, efficient materials for solar fuels production and utilisation is a challenging goal but the potential impact is enormous. An improved understanding of surface mechanisms on current materials would represent an important step towards this ambition.

The fellowship will accelerate the delivery of advanced materials for the light driven production of fuels and explore the chemistry of fuel utilisation. The preparation of a low cost efficient material that uses solar energy to drive the production of a fuel from water and CO2 would transform the energy landscape and the economic, societal and environmental impact would be vast.

Society/environment: EPSRC research priorities in Energy are designed to help the UK meet Government targets for energy security of supply, cost and environmental impact. The UK has committed to an 80% reduction in carbon emissions from 1990 levels by 2050. This is a challenging goal and it will require the successful delivery of new materials for the sustainable production of fuels, the long-term goal of the fellowship. The catalysts developed will also help overcome the intermittency issues related to non-solar renewables enabling them to account for a larger portion of the UK's energy mix. CO2 reduction electrocatalysts and water splitting materials can also be developed for use in electrolysers for fuel production that can be coupled to existing infrastructure such as wind turbines allowing for energy storage during periods when electricity demand is low. The project will also address the mechanisms of fuel utilisation through fuel cell studies. Delivery of new vehicle fuel cells has the potential to addressing pressing public health issues relating to air pollution. The proposal also provides a route to obtaining value from an otherwise waste material, CO2. This has the potential to make long-term CO2 capture economically viable which would have significant medium term environmental and economic benefits. The utilisation and up-conversion of a fraction of a flue gas stream to high value products offers a route to off-setting the costs associated with CO2 capture and storage, making it feasible that fossil fuels could continue to be used in a low-carbon society.

The field of solar fuels, sometimes referred to as artificial photosynthesis is largely unknown to the general public. If the technologies developed are to gain general acceptance it is important that the underlying principles and advantages (both economic and environmental) are relayed at an early stage. The sudden arrival of a disruptive technology can lead to understandable concerns and resistance. Therefore I will use a portion of the fellowship time to carry out public lectures, develop new demonstrations and to organise interactive features for open-days.

Industry: A positive impact will be generated in the short term via the industrial partners already identified (Ceres Power, Johnson Matthey and ITM power, see letters of support). These companies highlight a specific need for surface sensitive measurements that can help them solve critical questions with their individual technologies and are keen to also seek additional SFG instrument time on topics beyond the fellowships remit. Assisting the product development of the industrial partners could provide economic benefits to the UK through increased employment and taxation. Working with these partners also offers a route to delivering environmental impact as the technologies studied (fuel cells, emission control catalysis, electrolysers) will help enable a low carbon economy. During the fellowship the number of industrial partners is likely to expand as the experiments become established and advertised to the community. This project will be supported by the Knowledge Centre for Materials Chemistry (KCMC, see attached letter). KCMC will assist in the promotion of the project to potential partners and they have an excellent track record in establishing new collaborative partnerships between UoL academics and industry. In the long-term the delivery of new materials for solar fuels production has the potential to lead to the formation of new industries and to provide low cost fuels for both residential and industrial customers.