Skip to main content

ZEOlites for the conversion of CO2 to fuels and chemicals

Periodic Reporting for period 1 - ZEOCO2 (ZEOlites for the conversion of CO2 to fuels and chemicals)

Reporting period: 2018-05-01 to 2020-04-30

Climate and pollution concern, feedstock availability and geopolitical issues stress the need for alternative sustainable processes for the production of chemicals and fuels. In this sense, the conversion of CO2 to valuable compounds containing more than one carbon is a grand challenge of our time. Among different strategies of using CO2 as a carbon feedstock, classic thermo-catalytic methods, should also be pursued, due to the simple recovery and recycle of solid catalysts able to work under high temperature and pressure conditions. Key however is to devise a process that is cost- and energy-efficient, while able to satisfy the rising demand of chemicals and fuels in a sustainable way. Although in its infancy, the direct hydrogenation of the CO2 to methanol combined with further C-C coupling into value-added products with two or more carbons is a very promising gas-to-liquid process. This direct strategy allows for the obtention of methanol, light olefins or gasoline, with a reduced number of steps and minimized chemical waste, and should help to reach fossil-fuel independency, relevant in EU, and the consumption of greenhouse gas, reducing its emissions at the source. Therefore, this integration can contribute to a more environmentally benign CO2 recycling strategy, i.e. CO2 as feedstock, as dictated by the EU environmental policy for ‘secure, clean and efficient energy’ through chemical transformation into high-volume added value products. In this fellowship, the introduction of different active sites, spatially isolated, but within the same solid matrix, would allow to carry out hydrogenation and C-C coupling with one catalyst. The rationale for the design and use of a new type of inexpensive, stable and catalytically active microporous hybrid zeolite for CO2-conversion is based on the design of novel multifunctional zeolites with tuned physico-chemical properties in an affordable way.
The project has achieved most of its objectives and milestones for the period, with relatively minor deviations. The specific work performed from the beginning of the project has achieve the following aspects:
1)Design novel multifunctional zeolites with tuned physico-chemical properties in an affordable way. The work carried out was based on the design and synthesis of MOF derived Cu and Zn species directly incorporated on zeolites for the first time via co-calcination of Cu or Zn MOFs with porous aluminosilicates. The poor catalytic activity on the hydrogenation of CO2 to olefins/hydrocarbons exhibited by these materials does not encourage us to proceed with further investigations using Cu redox active sites. This insufficient activity was probably due to the very low metal loadings obtained by these synthetic procedure making impossible the obtention of enough CO2 conversion values (higher metal loading resulted in the agglomeration and deactivation of the Cu and Zn species). However, in order to take profit of the materials synthesized by this methodology a collaboration was established within KULeuven working on catalytic technologies in fine chemistry.
2)Apply these zeolite solids as heterogeneous catalysts for the sustainable synthesis of methanol, olefins and fuels from CO2. The application of the different heterogeneous catalysts was based on the new synthetic methodology related to MOF derivatives and small pore zeolites for the selective conversion of CO2 into light olefins, using the lowest metal loadings reported in literature. The catalyst synthesis involves deriving In-Zr oxides from MOFs containing these metals in their structure, via direct calcination in the presence of the zeolite, avoiding co-precipitation, washing and mixing steps. This effectively creates a truly bifunctional (redox and acid) In-Zr zeolite catalyst, opposed to physical mixtures of two catalysts using different precursors. The good dispersion and low loadings of the MOF- derived In-Zr oxide, supplemented with the strong acidity of small pore zeolites allows to couple the activation of CO2 with C-C coupling. The catalytic performance of the samples results into space time yields of about 0.1 mol of CO2 converted to light olefins per gram of In per hour at the relatively mild temperatures of 375ºC, which is among the highest olefin production values reported in literature.
3)Understand the structure, composition and deactivation of catalytic nanodomains of working hybrid heterogeneous catalysts under in-situ conditions by spectroscopic techniques applied to the zeolite crystals.
This was achieved, in base on the obtention of correlations between catalytic performance (activity or selectivity) and structural reactivity parameters such as acidity, metal active site loading, aggregation and porous structure using several characterization techniques, e.g. XRD, N2 adsorption, ICP, TGA, TPD, TPR, XAS, TEM microscopy.
The impact of this project is clear given the successful publications in high quality journals, as first author: ACS Catalysis (IF: 12,2), and ChemCatChem (IF: 4.7) (under review, revision request received). The first one is available in open access (repository Lirias) and the second one will be as soon as it is accepted. Another important impact of this project in the researcher career primarily consists of training through research in a team-work environment that has foster the social competence including (self-) management and leadership. In particular the communication and leadership skills have been enhanced as well as participation at meetings and oral presentations at international conferences of the highest quality in chemistry, and inspire students and encourage other researchers with their career through internet dissemination tools, such as the research group website, researchgate or twitter (@ZEOCO2), but also in events organized by the University of Leuven, Pint of Science, etc., in addition to supervise, support and develop undergraduate and PhD students from KU-Leuven, the bioengineering department and visiting students from other institutes or universities. The Fellowship has enhanced the researcher’s ability to obtain and manage funding, being awarded a University of Valencia with one of the most competitive postdoctoral research contract (Juan de la Cierva call-2018). Beside the obtention of funding, the MSCA-IF has helped the researcher with the research prizes, such as the international Borealis Innovation Award for recently PhD graduated researchers (2019), Best PhD thesis on chemistry developed at Technical University of Valencia (2018), finalist of the international Umicore Materials Award (2018) and best poster contribution award of the Dutch Zeolite Association meeting. The work carried out enhances innovation capacity, create perspectives for new hybrid catalyst technology with potential market opportunities and address industrial needs in the petrochemical / CO2 / fine chemical sector. In particular, the new synthetic methodologies of active catalyst and their application in the CO2 valorization, contribute towards European policy objectives (e.g. green synthesis of polymer precursors, bulk chemicals, sustainable use of resources, etc.) by ensuring an efficient transfer of knowledge between academy and industry, the enhancement of European leadership in materials chemistry and petrochemical production, and the acceleration of the implementation of these materials and processes in Europe and in the world.
Graphical abstract of the project results