Innovative photocatalysts integrated in flow photoreactor systems for direct CO2 and H2O conversion into solar fuels

Project Information

NEFERTITI

Grant agreement ID: 101022202

DOI

10.3030/101022202

Project closed

EC signature date 9 April 2021

Start date 1 July 2021

End date 31 December 2025

Funded under

• SOCIETAL CHALLENGES - Secure, clean and efficient energy

Total cost

€ 4 312 287,50

EU contribution

€ 3 844 427,50

Coordinated by

ACONDICIONAMIENTO TARRASENSE ASSOCIACION
Spain

Periodic Reporting for period 2 - NEFERTITI (Innovative photocatalysts integrated in flow photoreactor systems for direct CO2 and H2O conversion into solar fuels)

Reporting period: 2023-01-01 to 2024-06-30

Summary of the context and overall objectives of the project

In the context of the current quest for the energy system transformation, it is key to phase out the fossil fuels and replace them by more sustainable energy carries. Ambitious targets were set to shift the energy mix to a higher share of renewable energies, with the aim to eliminate greenhouse gas emissions (GHG).
Solar fuels produced by photocatalysis, photoelectrocatalysis or biological/biochemical systems, have a potential to significantly contribute to achieving the ambitions set by the international community, but a number of technological challenges still need to be overcome to bring these technologies from the lab to the market. Photocatalysis, which is currently in its infancy, has the potential to outperform the above thanks to its lower cost (system setup), easily tunable catalysts and longer lifetime. Integration of processes that mimic nature is a great ambition that, once achieved, can open doors to the important discovery of a new environmental-friendly way to reach the decarbonization goals. By investigating the reaction mechanisms for the photocatalytic CO2/H2O conversion and C-C bond formation to C2+ alcohols in continuous flow, an unprecedented research activity, NEFERTITI aims to go beyond the state-of-the-art and make a step change in the development of this highly promising solar fuel technology. Its advanced process requiring the optimal combination of stable photocatalytic materials, photosensitisers and the use of flow technology will be led by a cutting-edge multidisciplinary international consortium from EU, China and the USA, supported by an international panel of stakeholders in the NEFERTITI Advisory Board.
The overall aim of the project NEFERTITI is to develop an innovative highly efficient photocatalytic system enabling a simultaneous conversion of CO2 and H2O into solar fuels (ethanol and alcohols with longer chain such as (iso)propanol).
This system will provide a breakthrough alternative to transform CO2 into valuable products for energy and transport. To accomplish this objective, NEFERTITI will use novel heterogeneous catalysts (Covalent organic frameworks and metal oxides combined with metallic nanoparticles) and luminescent solar concentrators into two Photocatalytic flow reactors sourced by sunlight energy.
The main objectives of the project are the following:
• Synthesize enhanced photocatalysts allowing syngas production with an increased solar-to-CO efficiency
• Synthesize enhanced photocatalysts to produce ethanol from CO and H2
• Synthesize specific photosensitizers to match the maximum absorption of the photocatalysts
• Design novel continuous flow photoreactors to enhance the efficiency of the alcohols synthesis
• Purify the generated EtOH
• Integrate both flow reactors and validate it at TRL4
• Produce ethanol, lowering the costs and reducing the CO2 footprint
• Increase the overall chemical energy conversion efficiency, compared to batch reactions
• Save energy due to the use of sunlight
• Establish a long-lasting collaboration between EU, China and the USA

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Lots of work has been carried out during the first 36 months of the project by all the partners.
In WP1, the requirements and parameters for the photocatalysts and for both PCFR1 and PCFR2 were defined. Moreover, Leitat tried to increase the solubility of CO2 in water, because of the results obtained, it was decided to work in “wet” CO2 for the rest of the project.
In WP2, NUIG has been working on the synthesis and optimisation of 2D-COF catalysts achieving different options that will be tested in the following months to select the best one and test it in the real NEFERTITI system. This synthesis takes more than 10 steps and thus, results in low yields. Nevertheless, the catalyst can be obtained in very high purity. During the last months, the anchoring of this catalyst has also been studied and will be ready soon for the final tests. Different strategies based on metal-glass interactions have been selected. Moreover, light harvesting systems have been developed and will be optimized in the following months (LSC and lens system).
Regarding the synthesis of alcohols from CO and H2 in WP3, PKU has been working on the development of more than 5 different types of photocatalysts, including different metals such as Ni, Ti, Fe, Rh, Cu, Mn, Li among others. Finally, a Rh based catalyst was selected as the best option for the reaction, achieving c2+ alcohols in more than 35-40% selectivity. In the same way as WP2, different techniques for the anchoring of the catalyst were studied and the results will be obtained in the following months. The light harvesting systems in this case were the same ones that were found in WP2.
In WP4, UBU has been working on the development of a CFD model to help in the scaling up process and try to optimise the big scale system. In addition, SOCAR started with the conditioning of their facilities to test the big scale system in the following months. In parallel, Leitat is studying the water/ethanol purification through a previously synthetized membrane using pervaporation technique.
In parallel to the experimental results, a toxicological evaluation of the materials used was developed in WP5 by UBU. In addition, LCA and human and environmental assessment will be finished in the following months.
In WP6, STRATA together with Leitat has developed all the communication and dissemination material of the project, including the roll-up, the leaflet and the diptics. Moreover, the website of the project has been developed.
The project was disseminated through conferences and workshops, and it was exploited by means of scientific publications.
Finally, all the project has been coordinated by Leitat through WP7. Among other activities, regular meetings were held online to share and discuss the results with all the partners. Moreover, hybrid meetings were held every 6 months.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

NEFERTITI is structured in 4 stages:
• Continuous Flow Photoreactors: NEFERTITI photocatalysts will be immobilized in the inner walls of the reactor to avoid both catalyst leaching and separation steps and increase the yield. Flow reactors will be designed and tailor-made to support each catalyst and optimize the catalytic properties. This will afford a more stable and efficient product synthesis.
• Photosensitisers as light harvesting systems: NEFERTITI will use photosensitisers to improve photocatalyst absorption. Photosensitisers will be deposited at the external part of the flow reactors to maximise the light harvesting, leading to a more efficient process.
• NEFERTITI integrated device: Integrated continuous flow device to generate fuels by photocatalytic reactions will be validated for the first time. Two sequential flow reactions will be performed in just an integrated flow device. Moreover, this process will allow to produce other value-added compounds such as olefins, hydrocarbons, aromatics... by just changing catalysts or conditions of the second flow reactors.
• Membranes unit for EtOH purification: MMM achieving increased separation factors (liquid solar fuels from water and unreacted feedstock up to 90 %) & stability (>500h). Novel mixed matrix membranes will be developed considering the obtained products in PCFR2.

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