Title : Effect of catalyst acidity and reduction step on carbon dioxide valorization
Abstract:
Over the last decades, carbon dioxide (CO2) is incessantly accumulated in the atmosphere due to human activities, especially in countries with developed economies. CO2 constitutes one of the main greenhouse gases and CO2 emissions are linked with global warming and several environmental concerns, thus strategies and technologies for immediate mitigation of CO2 emissions should be adapted. CO2 valorization techniques have been developed, using CO2 as feedstock for the production of high added value products (chemicals and/or fuels) by heterogeneous catalysts with multifunctional structures. Within this context, mixed metal-based oxides were synthesized in order to catalyze the Reverse Water-Shift (RWGS) reaction (CO2 is converted into CO), as well as Fischer – Tropsch (FTS) like reactions (CO hydrogenation). Alkali promoters were added to enhance selectivity into olefins, while the synthesized oxides were dispersed on acidic supports that promote deoxygenation reactions. Preliminary experiments were conducted to elucidate the effect of the reduction of the metal oxides and the zeolitic acidity/SAR on materials’ catalytic performance. Samples were reduced for four hours prior to RWGS resulting in the production of C1-C3 deoxygenated species, such as methane, ethane, propene and propane. Further reduction did not improve CO2 conversion and selective product distribution. Overall, reduced alkali promoted magnetite nanoparticles dispersed on H-ZSM5 (140-160 SAR) showed the most promising results with 9.3% CO2 conversion, as well as 16.4 and 81.1% selectivity to CO and methane, accordingly.
Acknowledgements
We acknowledge support of this work by the project “PROMETHEUS: A Research Infrastructure for the Integrated Energy Chain” (MIS 5002704) which is implemented under the Action “Reinforcement of the Research and Innovation Infrastructure”, funded by the Operational Programme "Competitiveness, Entrepreneurship and Innovation" (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund).
Audience Takeaway:
- Catalytic carbon dioxide valorization aspects
- Effect of specific catalytic properties on the reaction product distribution
