BUBBLE-AFM: Molecular processes at electrode/electrolyte interfaces during water electrolysis: from solvent restructuring to nanobubble nucleation

Programme?Horizon Europe – COFUNDReference NumberPRISM-2026-754691Marie Curie Grant Agreement Number101261637Is the Job related to staff position within a Research Infrastructure?Yes

Offer Description

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

BUBBLE-AFM: Molecular processes at electrode/electrolyte interfaces during water electrolysis: from solvent restructuring to nanobubble nucleation

The transition toward sustainable energy systems critically relies on the development of efficient water electrolysis technologies for green hydrogen production. However, the performance of electrolyzers is strongly limited by the formation, growth, and adhesion of gas bubbles at electrode surfaces, which block active sites, increase local resistance, and alter mass transport near the interface. Despite extensive studies, the fundamental mechanisms governing the earliest stages of bubble nucleation, occurring at the nanometric scale, remain poorly understood due to the lack of suitable in situ characterization techniques.

This PhD proposal aims to address this major knowledge gap by developing an innovative experimental approach combining electrochemical control with in situ Atomic Force Microscopy (AFM) in liquid environments. Building on recent advances and the installation of a new electrochemical AFM platform within the ESPCI premises, the project will provide unprecedented access to molecular-scale processes occurring at electrode/electrolyte interfaces during water electrolysis. In particular, it seeks to elucidate the transition from solvent restructuring under applied potential to gas supersaturation and ultimately nanobubble nucleation.

The scientific rationale rests on the hypothesis that bubble nucleation is a metastable process governed by a subtle interplay between local surface properties (chemistry, wettability, roughness, defects) and electrochemical conditions. To get novel fundamental insights into this process, we will first focus on model electrodes (e.g., graphite). We will rely on high-speed and high-resolution dynamic force spectroscopy of near-surface structural and solvation forces, which will provide insight into the early stages of bubble nucleation — from solvent restructuring under electrochemical potential, to interfacial gas saturation, to bubble nucleation and growth kinetics. We will then extend our investigations towards more realistic electrodes, using high-resolution imaging of surface nanobubbles to correlate local bubble nucleation with surface chemistry (hydrophilicity/hydrophobicity balance), topography, and defects. Together, these measurements will help identify nucleation pathways and clarify the role of surface heterogeneities in triggering bubble formation.

A second objective will then be to establish quantitative correlations between these nanoscale observations and macroscopic electrochemical performance. By systematically varying electrode materials and surface treatments, we will aim to determine how local interfacial phenomena influence global efficiency, thereby providing guidelines for the rational design of improved electrodes with reduced bubble-related losses.

Overall, this PhD project is highly innovative in its ability to access previously inaccessible interfacial phenomena at the nanoscale and to bridge the gap between interfacial soft matter, solid/liquid interfaces, fundamental surface science and applied electrochemical engineering. Its expected outcomes will contribute to both fundamental understanding and technological advances in hydrogen production, positioning it at the forefront of research on energy-related interfacial processes.

References

1. Kempler, P. A., Coridan, R. H., & Luo, L. (2024). Gas evolution in water electrolysis. Chemical reviews, 124(19), 10964-11007.
2. Zhang, L., Zhang, Y., Zhang, X., Li, Z., Shen, G., Ye, M., ... & Hu, J. (2006). Electrochemically controlled formation and growth of hydrogen nanobubbles. Langmuir, 22(19), 8109-8113.
3. Utsunomiya, T., Yokota, Y., Enoki, T., & Fukui, K. I. (2014). Potential-dependent hydration structures at aqueous solution/graphite interfaces by electrochemical frequency modulation atomic force microscopy. Chemical Communications, 50(98), 15537-15540.
4. Martin-Jimenez, D., Chacon, E., Tarazona, P., & Garcia, R. (2016). Atomically resolved threedimensional structures of electrolyte aqueous solutions near a solid surface. Nature communications, 7(1), 12164.
5. Comtet, Jean, et al. "Nanoscale capillary freezing of ionic liquids confined between metallic interfaces and the role of electronic screening." Nature materials 16.6 (2017): 634-639.

3i dimensions

INTERNATIONAL: The project has a strong international dimension through established and planned collaborations with leading experts in interfacial science and advanced AFM, providing complementary expertise in confined electrolyte studies under surface-force apparatus, molecular-scale characterization of solid–liquid interfaces, and interfacial liquid structuring. The compulsory international secondment (minimum one month) will ideally take place at one of these partner laboratories, enabling knowledge transfer, access to complementary instrumentation, and strengthening the international impact and visibility of the project.

INTERSECTORAL: The project has a strong intersectoral potential through its direct relevance to industrial challenges in hydrogen production and surface engineering. A collaboration or secondment with an industrial partner such as TotalEnergies or Saint-Gobain will be sought to investigate the role of engineered surface coatings and functional interfaces on gas bubble nucleation, growth and detachment during water electrolysis. Initial contacts have already been established with both companies, providing a solid basis for future interactions, although no formal partnership has yet been implemented. Such a collaboration would facilitate the transfer of fundamental nanoscale insights toward the optimization of industrial electrode materials, while exposing the PhD candidate to innovation-driven research and technology development in a non-academic environment.

INTERDISCIPLINARY: The project is highly interdisciplinary, bridging together concepts in interfacial physics, soft matter, electrochemistry, surface science and electrocatalysis. It combines advanced scanning probe microscopy, molecular-scale characterization of solid–liquid interfaces, electrochemical measurements and materials engineering to investigate gas bubble nucleation during water electrolysis. By linking nanoscale interfacial phenomena to macroscopic electrochemical performance, the project integrates fundamental physics and physical chemistry with challenges in energy conversion and materials design. This cross-disciplinary approach will provide the PhD candidate with broad expertise spanning experimental nanoscience, electrochemistry, surface engineering and data analysis, while fostering interactions between complementary scientific communities.

Where to apply

Website: https://prism.psl.eu/

Requirements

Research Field: Physics

Education Level: Master Degree or equivalent

Skills/Qualifications

We are looking for a master's student with a background in physics, materials science, electrochemistry, or physical chemistry, who is excited to dive into an interdisciplinary project at the crossroads of soft matter, interfacial physics and physico-chemistry, liquid-state physics, electrochemistry, and electrocatalysis. The envisioned AFM experiments are technically demanding and require great care and precision: a strong aptitude for hands-on experimental work with complex, custom-built instruments — here, Atomic Force Microscopy — together with solid data analysis skills, will be key to making the most of this project. Beyond technical background, we are above all looking for someone curious, open-minded, and able to think independently, who is eager to take ownership of a research question at the frontier of physics and electrochemistry.

Languages: ENGLISH

Level: Excellent

Research Field: Physics

Years of Research Experience: 1 - 4

Additional Information

Benefits

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.

Eligibility criteria

1. At the time of application, candidates must be in possession of their Master’s degree or equivalent/postgraduate degree which formally entitles them to start a doctorate. All applicants with a doctoral degree are ineligible.
2. A minimum English proficiency level of C1 (Advanced) is required for applicants from non-English-speaking countries. No French language skills are required.
3. Applicants must fulfil the transnational mobility rule: open to all nationalities but all incoming applicants must not have resided or carried out their main activity (work, studies, etc.) in France for more than 12 months in the 3 years immediately prior to the call for applications deadline.
4. Applicants must be available to start the program on schedule: 1st March 2027.
5. Completeness of the application, submitted in English on the PRISM dedicated website, before the deadline of 31 October 2026.

Selection process

The applications will go through the following assessment steps:

1. Eligibility check to ensure the administrative compliance of the applications (mandatory documents provided and eligibility conditions met; see section “application eligibility”).
2. Remote evaluation of each application by different reviewers depending on the open PhD projects selected by the applicants. The selected applicants will be informed of their results, their ranking and invited to participate in the next step of interviews. Unsuccessful applicants will receive a detailed report by email.
3. Interview and selection of the shortlisted applicants via videoconference, comprising:

• A presentation (maximum 10 minutes) by the applicant of their motivation for applying to the program, including their experience and training in the field. Applicants will be explicitly asked to explain the fundamentals of the selected PhD research project and its scientific literature. The applicant will have the opportunity to make suggestions to shape their future PhD project.
• A series of questions (10 minutes) put by the committee to the applicant. These will include technical questions on the fundamentals of the topic. In addition, in the interests of fairness, a list of common questions will be asked to each applicant.

1. Recruitment: once a candidate has been selected and has accepted the offer, the management team will initiate their recruitment process. For some nationalities, in compliance with French national requirements, the mandatory security clearance procedure will be launched at the final stage of recruitment. In the event of an unfavourable decision, the position will be offered to the next candidate on the reserve list.

Additional comments

Name of the school of PSL

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

Research Unit

Soft Matter Science and Engineering (UMR 7615, SIMM)

Institute of Porous MAterials of Paris (UMR 8004, IMAP)

The project team brings together complementary expertise from two researchers, J. Comtet and L. Assaud, based in two ESPCI research units: the Soft Matter Science and Engineering Laboratory (SIMM) and the Institute of Porous Materials of Paris (IMAP). J. Comtet's research focuses on probing the transport and dynamics of soft matter at interfaces, at the nano- and molecular scale, using innovative experimental approaches ranging from scanning probe to single-molecule imaging. L. Assaud's work centers on the characterization and optimization of novel two-dimensional electrochemical interfaces and electrocatalytic processes through nanostructuration. This project is thus unique in bringing together complementary expertise in electrochemistry (IMAP), wetting and solid/liquid interfaces (SIMM), and quantitative scanning probe microscopy (IMAP, SIMM). By combining in situ electrochemical AFM with systematic surface engineering to directly observe the nucleation and early growth of gas bubbles at the nanoscale, this approach will enable the exploration of interfacial material properties at the nanometric scales, and open new avenues for the design of highly efficient electrodes for water electrolysis.

Supervision

Supervisor: Jean Comtet jean.comtet@espci.fr

Co-supervisor: Loic Assaud loic.assaud@espci.fr

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.

Keywords

Solid/liquid interfaces, nanobubbles, nanofluidics, electrocatalysis, energy, hydrogen, Atomic Force Microscopy

Website for additional job details: https://blog.espci.fr/jcomtet/2026/07/27/prism/

Work Location(s)

Number of offers available: 1

Company/Institute: ESPCI PARIS PSL

Country: France

City: Paris

Postal Code: 75005

Street: 10 Rue Vauquelin

Contact

City: Paris Cedex 05

Website: https://blog.espci.fr/jcomtet/

Street: 10 rue Vauquelin

Postal Code: 75231

E-Mail: contact@prism.psl.eu