STREAM - Seawater Treatment for CO2 Removal via Electrochemical Microelectrode Arrays

PRISM programme

The PRISM (PhD Research Programme for International Training in Sustainable Soft Matter) programme has launched its first call for applications, offering up to 14 fully funded PhD fellowships starting from 1 March 2027 at Paris Sciences & Lettres (PSL) University. The programme trains researchers to address ecological transition challenges through sustainable soft matter science, with projects focused on eco-friendly chemical processes, circular economy, renewable energies, and carbon capture, storage, and valorisation. Co-funded by the European Union under Horizon Europe MSCA COFUND (Grant Agreement 101261637) and partner institutions, PRISM provides interdisciplinary, international, and intersectoral training, including mobility opportunities, secondments, and courses in sustainability, innovation, entrepreneurship, career development, and transferable skills.

Applications must be submitted via the PRISM website by 31 October 2026 (23:59 Paris time).                                                                    

The PhD project

Among negative-emission strategies, direct CO₂ capture from oceans and seawater is particularly attractive because these reservoirs contain about 150 times more dissolved CO₂ than the atmosphere. Several electrochemical approaches have been proposed, including bipolar membrane electrodialysis, chloride-mediated electrochemical acidification, and electrochemical hydrogen looping. The latter has demonstrated up to 91% CO₂ capture efficiency with an energy consumption of 2.4 GJ per ton of captured CO₂. However, many existing approaches overlook potential contamination and material integrity associated with large pH swings and long-term exposure to corrosive environments. Future developments must therefore prioritize the chemical and mechanical stability of materials under extreme pH and salinity conditions, alongside comprehensive techno-economic and life-cycle assessments of technology [1-6].

This PhD project aims to design innovative reactor architectures based on microelectrode arrays capable of generating local pH swings without chemical additives or ion-exchange membranes. The system enables direct CO₂ extraction from ocean or seawater, followed by either on-site storage or further electrochemical conversion into value-added products. The CO₂ capture relies on two key coupled electrochemical principles: (i) shifting the HCO₃⁻/CO₂ equilibrium towards CO₂ through local acidification near the electrode surface, and (ii) electrochemically converting the released CO₂ to CO, maintaining the bulk pH close to its initial value. This is achieved through integrated microelectrode arrays (MEAs) with micrometer-scale gaps between paired anodes and cathodes, thereby enabling strong spatial confinement of proton and hydroxide fluxes. Local acidification is driven by anodic water oxidation, followed by pH neutralization and buffering in the cathodic CO₂ reduction and hydrogen evolution reactions; the latter contribution can be minimized by selecting an appropriate catalyst.

The proposed approach offers several advantages over the state-of-the-art CO₂ extraction systems. First, it enables a simplified reactor design by eliminating the need for costly ion exchange membranes. Second, the process avoids excessive local pH increase, which can promote unwanted carbonate precipitation at the electrode. CO₂ generated close to the anode and not valorized in step 2 at the cathode will be extracted under a small vacuum (along with produced CO) through the designed multilayer gas diffusion electrode (GDE).

Over the course of the PhD, this concept will be translated into an integrated flow reactor that combines patterned MEAs, porous transport layers and a multilayer GDE optimized for operation in increasingly complex electrolytes, up to real seawater. The expected outcome is a reactor architecture that maintains high CO₂-to-CO selectivity at low cell voltage, with limited metal leaching and stable performance over extended operation. A key objective will be to map the operating window (current density, flow rate, salinity and temperature) that maximizes CO₂ extraction efficiency and energy performance, providing quantitative benchmarks for comparison with existing CO₂-from-seawater technologies.

Building on this platform, the project is expected to deliver optimized MEA designs in which mass transport is actively engineered through microelectrode geometry (electrode size, gap and spacing), tailored PTL/GDL porosity and controlled flow conditions. Catalyst development will focus on robust, low- to non-precious-metal formulations (e.g. Ni-based materials, with small or no addition of Ir, or Au/Ag) synthesized by a combination of thin-film deposition (ALD, PECVD, PVD) and electrodeposition directly on porous supports, with composition and microstructure systematically varied from model electrodes to full MEAs. Performance and degradation mechanisms will be elucidated using operando AFM-based imaging, electrochemical testing and gas/liquid product analysis, establishing clear links between catalyst design, MEA architecture and mass transport. Together, these results will provide experimentally grounded design rules and a versatile, high-impact research framework for a PhD project spanning catalyst synthesis, reactor engineering and advanced characterization.

3i dimensions

INTERNATIONAL: The project has a strong international dimension through its alignment with global research on carbon-neutral technologies, seawater-based CO₂ capture, and electrochemical energy conversion. It addresses scientific challenges of worldwide relevance and connects with international communities working on carbon capture and utilization, electrochemical reactor engineering, and sustainable fuels. International collaborations will be strengthened through two short research stays: (i) with Prof. Ulrike Krewer and Dr. Philipp Röse (Karlsruhe Institute of Technology, Germany) on kinetic modelling and local pH effects in CO₂ electroreduction, and (ii) with Prof. Emiliana Fabbri (Paul Scherrer Institute, Switzerland) on operando spectroelectrochemical characterization. Participation in international conferences, workshops, and research networks will further enhance the candidate’s integration into the global scientific community.

INTERSECTORAL: The project has a strong intersectoral dimension by combining fundamental electrochemistry, materials engineering, and reactor development for sustainable carbon capture and utilization. It addresses key challenges for industrial deployment, including catalyst durability, corrosion resistance, energy efficiency, and scalable reactor design. The proposed microelectrode-array reactor, which controls local pH without chemical additives or ion-exchange membranes, offers significant innovation potential by reducing system complexity, cost, and environmental impact. The multidisciplinary approach creates opportunities for collaboration with industrial partners in carbon capture, electrolysis, and sustainable energy. The project also builds on the ongoing collaboration between the CBI-MIE team and TotalEnergies on advanced electrodes and CO₂ electroreduction, extending this work toward direct CO₂ capture and conversion from seawater.

INTERDISCIPLINARY: The project is highly interdisciplinary, integrating electrochemistry, materials science, chemical engineering, physics, and microfabrication. It combines catalyst design, surface chemistry, transport phenomena, interfacial physics, and reactor engineering to develop efficient seawater-based CO₂ capture and conversion systems. Advanced materials processing and operando characterization are coupled with microstructured reactor design, while techno-economic and sustainability aspects ensure relevance for scalable carbon management technologies.

References:

[1] Eisaman, M. D. et al. Energy Environ Sci 5, 7346 (2012),

[2] Digdaya, I. A. et al. Nat Commun 11, 4412 (2020),

[3] Kim, S. et al. Energy Environ Sci 16, 2030–2044 (2023),

[4] Yan, L. et al. ACS Energy Lett 7, 1947–1952 (2022),

[5] Macounová, K. et al. Anal Chem 72, 3745–3751 (2000),

[6] Monteiro, M. C. O. et al. Nat Commun 12, 4943 (2021)

Salary

The PRISM programme offers a competitive salary above the national average for PhD candidates in France to attract and support excellent researchers.

Doctoral candidates will receive an approximate net monthly salary of €2,200, with additional family and mobility allowances available for eligible fellows.

The salary is subject to French income tax, with the exception of the family and mobility allowances. Depending on the candidate's individual tax situation, income tax may represent approximately 2–5% of the net salary and is levied by the French tax authorities independently of the employer.

To ensure consistent management and equal employment conditions across the programme, all PRISM doctoral candidates will be employed by ESPCI Paris, regardless of the host laboratory where their research is carried out.

Employer’s benefits

Remote working opportunities, access to sports and leisure activities, free access to public Paris city council’s swimming pools, access to CROUS canteen, scientific campus in central Paris, professional development programs, well-being workshops, social benefits through CNAS, partial health insurance support, and 75% support for sustainable mobility.

Name of the school of PSL

ESPCI Paris - PSL (Ecole Supérieure de Physique et de Chimie Industrielles de la Ville de Paris)

Research Unit

Institute of Porous Materials of Paris, UMR 8004, IMAP

Institute Chemistry Biology Innovation, UMR 8231, CBI-MIE

This PhD project will be carried out in collaboration between the Institute of Porous Materials of Paris (IMAP, UMR 8004), and the MIE (Materials, Innovation, Energy) team of the institute Chemistry Biology Innovation (CBI, UMR 8231). IMAP laboratory focuses on the development and multiphysical characterization of functional porous materials and their applications in the fields of health (drug delivery, biomaterials), energy (batteries, hydrogen, etc.), and the environment (CO₂ capture, sensing, etc.). The group’s research strongly focuses on electrocatalysis for sustainable hydrogen production, CO₂ electroreduction, and membrane-based electrochemical energy conversion technologies. The work explores the design and optimization of advanced catalysts, such as transition metal compounds and doped materials, to enhance the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and CO₂ reduction reaction (CO₂RR). The MIE team of the CBI laboratory focuses on understanding the mechanisms involved in the manufacture of materials. A major part of the team’s work is dedicated to studying the behavior of complex fluids under flow, confinement and instabilities occurring during film lamination or extrusion. This expertise supports the design of advanced energy materials and devices, including electrostrictive, piezoelectric, triboelectric, battery electrode, and CO₂ capture and electroreduction systems for low-power energy harvesting, storage, and conversion applications. The team also investigates the mechanisms of the reactions occurring at the electrode/electrolyte interface using a wide range of in situ and operando physicochemical characterization techniques, together with the development of devices operating under well controlled mass-transport conditions.

Supervision

Supervisor: ASSAUD Loïc loic.assaud@espci.psl.eu

Co-supervisor: OSHCHEPKOV Alexandr alexandr.oshchepkov@espci.psl.eu

Candidates are encouraged to contact the project supervisors to discuss the proposed research topics before applying. All projects are open PhD projects, meaning that the research plan will be further developed collaboratively by the selected doctoral candidate and the supervisors.

We are looking for a highly motivated, rigorous, and enthusiastic PhD candidate with an excellent academic background in physical chemistry, electrochemistry, chemical or energy engineering, materials chemistry, or a closely related field. The successful candidate should have a strong interest in interdisciplinary research at the interface of electrochemistry, catalyst development, materials science, and reactor engineering, with the ambition to contribute to both fundamental understanding and technological innovation.

A solid foundation in electrochemistry, including electrode kinetics, mass transport, interfacial phenomena, and electrochemical characterization techniques, is expected. Knowledge of fluid dynamics, transport phenomena, and chemical reaction engineering would be highly valuable, as the project involves the design and optimization of microstructured electrochemical reactors. Previous hands-on laboratory experience in electrochemistry, catalyst synthesis, materials characterization, or electrochemical reactor operation will be considered a strong asset.

Experience with computer-aided design (CAD) software for reactor or device design (e.g. Autodesk Fusion 360), numerical data analysis, or programming (particularly Python) would be advantageous. Familiarity with image analysis, simulation tools, or microfabrication techniques would also be appreciated but is not required.

The candidate should demonstrate scientific curiosity, critical thinking, and a proactive approach to research. They should be capable of working both independently and as part of a multidisciplinary team, with excellent organizational, communication, and problem-solving skills. Fluency in spoken and written English is essential, as the project involves international collaborations, scientific publications, and participation in conferences. A strong motivation to contribute to the development of sustainable electrochemical technologies for carbon capture and utilization is expected.