Optimizing Formate Production in Single-Chamber Electrochemical Cells using Low-Cost Bi and Sn Cathodes

The integration of electrochemical and microbial processes offers significant opportunities for CO₂ valorisation by leveraging the advantages of both domains. Electrochemical CO₂ reduction reaction) excels at using renewable electricity to generate simple intermediates (formic acid or acetate). Conversely, microorganisms can act as highly selective biocatalysts to synthesize a wide range of more complex high-value products such as bioplastics, fuels or chemicals. This tandem approach is the foundation for the novel CO₂-based industry.

eCO₂RR can be operated under ambient conditions at high rates and yields. This sets it apart from other CO₂ utilization technologies (biochemical, thermocatalytic, photosynthetic and photocatalytic). This project builds upon the work of Dr Zainab Ul Kausar, which demonstrated the viability of producing formate via eCO₂RR in a single-chamber (SC) cell configuration, with results comparable to double-chamber systems but with lower capital costs. A SC is ideal for its posterior one-pot integration with microbial systems.

While the original study successfully used indium (In) cathodes, this material’s high cost limits its large-scale industrial applicability. The primary goal of this new project is to evaluate and optimize the use of alternative, more economical cathode materials—specifically tin (Sn) and bismuth (Bi)—for the selective production of formate in SC systems. Previous studies have shown that Sn and Bi are efficient catalysts for eCO₂RR to formate. This research will systematically explore the performance of these cathodes under biocompatible conditions (near-neutral pH), which is crucial for future integration with microbial synthesis processes.

Objectives:

1. Fabricate and characterize Sn and Bi electrodes on carbon backbones, adapting the methodologies from Prof. Pellicer’s lab experience for electrodeposition.
2. Assess the Faradaic efficiency and formate production rate at various electrode potentials to determine the optimal operational window for each material.
3. Conduct extended duration experiments (>7 days) to evaluate the long-term stability of the Sn and Bi cathodes. This will involve analyzing performance degradation and potential catalyst leaching, which are critical factors for the process’s sustainability.
4. Directly compare the performance of the novel cathodes (Sn and Bi) with the results reported in the literature.

Based on the proposed project, a candidate researcher would need a combination of skills in electrochemistry, material science, analytical chemistry, and data analysis to successfully conduct this research. Thus, a candidate with a BSc/MSc in Chemical Engineering, Materials Science, or related fields would be suitable. The candidate will be guided in all the fields but some previous experience/knowledge is always valuable. Moreover, as all the PhD students, communication soft skills, ability for team work, methodological rigor, critical thinking, problem-solving and interdisciplinary mindset.

GENOCOV (Dr. Guisasola, Dr. Ul) stands for Group of biological treatment and of liquid and gaseous effluents, nutrient removal, and odors and Volatile Organic Compounds. The group is a research group from the Chemical Engineering Department at the Universitat Autònoma de Barcelona. GENOCOV, whose principal investigator is Prof. Francisco Javier Lafuente, has been active over the last 25 years in understanding the biological processes for the treatment of urban and industrial water and gaseous effluents, with special emphasis on monitoring, modelling and control of such complex biological systems. The quality of the research group can be measured at first sight through several quality indices such as several EU projects nd
projects funded by the Spanish Government. With respect to publications, in the last 5 years the group has more than 70 peer-reviewed international journals publications as well as an important participation in international conferences. The group consists nowadays of seven senior researchers: Francisco Javier Lafuente Javier Sancho (professor and head of the group), Juan Antonio Baeza Labat, Julian Carrera Muyo, David Gabriel Buguña, Albert Guisasola Canudas, Julio Perez Cañestro, María Eugenia Suárez Ojeda, in addition to around 20 active researchers (including postdocs, PhD students and lab technicians). More info can be found at
the research group website: https://www.genocov.com/

The Gnm³ group (Dr. E. Pellicer) belongs to the Physics Department at UAB and focuses part of its research on the design, synthesis, and characterization of advanced materials with tailored properties for cutting-edge engineering applications. We use electrodeposition to produce advanced material architectures with high surface-area-to-volume-ratios and compositions with reduced amounts of noble metals. These materials are used as electrodes in a variety of electrochemical reactions. Sustainability and energy efficiency are guiding principles of our work, shaping both the development of materials and their envisioned applications. More info can be found at the research group website: https://jsorticrea.uab.cat/research