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Soap Film based Artificial Photosynthesis

Periodic Reporting for period 2 - SoFiA (Soap Film based Artificial Photosynthesis)

Reporting period: 2020-01-01 to 2021-12-31

We propose a radical breakthrough by developing economically viable solar fuel production technology, exploiting the surfactant self-assembly & proton transport properties of soap films. Producing renewable solar fuel by Artificial Photosynthesis (AP) is globally recognized as a promising solution to modern energy & environmental crisis with decisive social impacts, but there are critical roadblocks in technology development. SoFiA aims to initiate & consolidate a baseline of feasibility for soap film based AP technology and its future uses by establishing the essential proofs-of principle & foundational scientific underpinnings. We propose the concept of an economic artificial photosynthetic membrane in form of soap film with photo-catalytic functional surfaces. Our technology is made scalable by the design concept of a dynamic stream of regenerative soap bubbles capable of handling large volumes of gas, continuously flowing through a light exposed conduit. SoFiA bridges three mutually exclusive disciplines of surfactant science, renewable energy and fundamental science of water at nanoscale, supported by micro-systems engineering, and by actively engaging artists who are working with large soap film installations. Our long-term vision is to decisively alter Europe’s position in the world economic map as the leading green energy producer. Developed technology will be jointly exploited by European energy and detergent industries, kick-starting new ventures & production facilities. Major environmental impact is expected as SoFiA is devoted to transform the primary greenhouse gas (CO2) into fuel and industrial feedstock.
Following is an overview of RP2 project status.
OBJ I. Lyophilization of water oxidation and CO2 reduction molecular catalysts that are based on abundant transition metals.
Status: Amphiphilic Ni-porphyrins have been synthesized, characterized and their efficiency as water oxidation catalysts (WOC) in micellar solution is currently under investigation. Report D4.1b (Annex to D4.1) completed with electrochemical data together with the synthesis of earth-abundant compounds. The Ru-based compounds remain up to now the best performing catalyst. Amphiphilic Co-porphyrin CO2 reduction catalysts have been developed and identified as the most active from a screening study that examined alkylated Fe, Co and Ni porphyrin and terpyridine complexes. Synthetic details and full characterization are in Report D4.1b while the screening study forms a manuscript currently under revision that will be included as an appendix to Report D4.3.
OBJ II. Selection and (if required) modification of water-soluble electron relays.
Status: We have thus identified a range of interesting candidates that we have begun testing.
OBJ III. Syntheses of photostable amphiphilic photosensitizers. Status: Different organic or zinc porphyrin-based photosensitizers have been synthesized and tested, but no AP in soap films could be obtained as yet. Ru(bpy)3-type photosensitizers remain the best photosensitizers for photocatalytic water oxidation and reduction. Report D4.1b completed with electrochemical data together with the synthesis of earth-abundant compounds. The selection of an earth-abundant photosensitizer showing comparable driving force and efficiency to the Ru-based one is still a challenging open question.
OBJ IV. By pioneering methodology, create dissymmetric soap film architecture with heterogeneous surfaces decorated with ionic, catalytic, photosensitizer surfactants; and with the water core containing electron relays.
Status: A microfluidic spray technique has been successful for doping soap films. Critical results have been obtained in model systems of surfactant class dyes where stable dissymmetry on soap film opposite surfaces exceeding designed residence time has been obtained (pioneering work) for ionic surfactants. For neutral model surfactant, the dissymmetry is lost. The results are being probed further.
OBJ V. Enable fundamental research in engineered monolayers (both in Langmuir & soap film), by design and fabrication of custom R&D platforms compatible with characterization instruments at partner facilities.
Status: Innovative designs have enabled fabrication of R&D platforms that is currently being used in our project, and can potentially be modified to further enable soap film and Langmuir film-based research.
OBJ VI. Advancing scientific knowledge on kinetics & transport mechanisms, associated with AP in engineered monolayers, using experiments supported by theoretical interpretations. The developed scientific knowledge will provide the optimal parameters and protocols for designing a POC demonstrator device. Demonstration of AP in Langmuir monolayers and in soap films within custom R&D platforms. AP on large area (4m2) custom Langmuir trough will be a contingency deliverable - SoFiA Plan B.
Status: Experimental, computational and modeling results have provided a molecular picture of the organization of amphiphilic photosensitizers and catalysts at air-water (Langmuir) multicomponent monolayers. Kinetic & transport measurements at liposomal interfaces as model membrane are completed; kinetic measurements in soap films and monolayers have been initiated and will continue during the remainder of the project. Custom Langmuir troughs have been made to optimize full AP. Photochemical CO2 reduction at air-water monolayers have been demonstrated in troughs, and partly optimized (preliminary report).
OBJ VII. Design, fabrication and characterization of AP POC demonstrator device.
Status: Design of modules for POC device have been updated significantly through experimental observations and modelling. Fabrication of Gen-1 modules are complete and testing has begun.
OBJ VIII. Engineering modelling optimization and simulation of the demonstrator device for providing estimates of scalability and potential design improvements.
Status: We have investigated a number of suitable modelling tools for engineering optimization of the demonstrator device, including computational fluid dynamics codes and dimensionless analysis. Such activities have enabled the identification of a preliminary set of key design parameters of the device along with their corresponding optimal values. Additional activities are on-going towards the aim of better refining both the modelling tools and their prediction accuracy.
OBJ IX. Test recyclability of functional molecules. Status: Associated task has not started yet.
OBJ X. Basic business plan. Status: A thorough study of IP landscaping has been done, and we have obtained a current project landscaping on AP from the Sunergy CSA. These documents along with techno-economic assessment in our final report will form foundations for our Basic business plan.
RP1: Progress beyond the state of the art has been initiated in all technical workpackages and is expected to be consolidated by RP2.

1. A key concept of disymmetry on a soap film was validated during RP2. It not only clears the roadmap for SoFiA but also opens up multiple channels for innovation in multiple diciplines using soap film and foam as a material of technological application.
2. CO2 reduction and Water Oxidation has been demonstrated on a soap film langmuir monolayer for the first time (according to our knowledge).
3. R&D platform with microfluidic frame for studying of soap film has been designed and fabricated.
Project Logo including project name and core concept of renewable solar fuels using soap bubbles.