CO2 emissions from the combustion of fossil fuels by man are the main cause of the anthropogenic greenhouse effect. Without drastic reduction of the CO2 emissions life conditions on earth will drastically change. On the other side fossil energy carriers are important "convenient" precursors of fuels and a number of chemical products which are fundamental bases of our way of life. Their availability is, even though not short-term, finite. An efficient and low-cost process for recycling of CO2 could contribute to reduce CO2 emissions and consumption of fossil resources. Of course, to reach these effects implies that energy carriers and possibly needed material inputs are made from regenerative resources. A promising approach is the photocatalytic CO2 reduction.
Goal of the project is the increase of yield and selectivity of the photocatalytic CO2 reduction to develop a new resource base for C(1+x) chemicals. For the base reaction mixture "CO2 + H2O" and the reference catalyst TiO2 up to now only very small conversion rates has been observed. To overcome the inactivity of the mixture and with that to reach economical yields two strategies are applied:
- Process management is optimized by adding reactive additives to the reaction mixture. As additives substances are used, which can be made from regenerative sources (e.g. H2 from electrolysis with PV power, bio-methane or bio-ethanol).
- New synthesis strategies for catalyst development shall lead to high efficient photocatalysts. Stoichiometry, porousness and defect structures of the materials shall be selectively controlled and the catalysts proved to be suitable for up-scaling.
Goal of the ITAS part is the supply of the system-analytical information to the partners which are necessary for the optimization of efficiency and sustainability of the new processes. Objects of the analyses are the environmental impacts and costs which will be investigated using life cycle related methods under the following aspects:
- Optimization of the PROPHECY process, integrated in chemical production systems and energy conversion systems.
- Ranking of the PROPHECY process and competing systems.
The life cycle related analyses also consider processes which are not direct objects of the R&D work in PROPHECY but unavoidable part of the overall system for producing the desired reduction products (construction of apparatuses, production of materials, production of additives etc.). So that it shall be ensured that no weak points in pre- and subsequent processes remain uncovered or even are caused by optimizations of the main process (e.g. new material with optimal functionality but increased environmental burden from production).
The analyses are conducted accompanying the R&D in close co-operation with the technical partners. That enables the use of sustainability information already in early phases of the R&D work and with it possibly necessary correction of the research direction with minimized effort.