Fuel forming electrocatalysis: Devising multifunctional covalent organic frameworks with vinylenic linkage for electrocatalytic CO2 reduction and water oxidation

Project Information

COFPOR-4-fuels

Grant agreement ID: 101105393

DOI

10.3030/101105393

Project closed

EC signature date 7 July 2023

Start date 15 January 2024

End date 14 January 2026

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 181 152,96

Coordinated by

FUNDACIO INSTITUT CATALA D'INVESTIGACIO QUIMICA
Spain

Periodic Reporting for period 1 - COFPOR-4-fuels (Fuel forming electrocatalysis: Devising multifunctional covalent organic frameworks with vinylenic linkage for electrocatalytic CO2 reduction and water oxidation)

Reporting period: 2024-01-15 to 2026-01-14

Summary of the context and overall objectives of the project

Reducing carbon dioxide emissions is one of the biggest scientific and societal challenges linked to climate change. One promising route is to turn carbon dioxide into useful fuels and chemicals using renewable electricity. This approach can help store renewable energy and reduce dependence on fossil resources. However, carbon dioxide is a very stable molecule, so it requires efficient and durable catalysts to convert it in a controlled way. This project focuses on a class of porous materials called covalent organic frameworks (COFs). COFs are crystalline, sponge-like solids built from light elements (such as carbon, nitrogen and oxygen). Their key advantage is that their structure can be designed at the molecular level. This makes them attractive for electrocatalysis, because the pores can be tuned to guide how molecules enter, react, and leave the catalyst.

The overall objective of the project is to develop robust COF-based electrocatalysts that can support two linked reactions: carbon dioxide reduction (converting carbon dioxide into value-added products), and water oxidation (the complementary reaction that can provide electrons and protons in an overall “artificial photosynthesis” concept). A second major objective is to understand how these catalysts work during operation. In many catalyst studies, performance is measured only by electrical signals (current). Here, the project aims to also detect chemical species formed at the electrode surface during electrolysis. This is important because it allows mechanism-guided catalyst design, which speeds up progress and reduces trial-and-error development.

The pathway to impact is stepwise: (1) design and synthesize COFs with controlled structure; (2) strengthen and tune the framework chemistry to improve stability and CO2 affinity; (3) evaluate performance for CO2 conversion and water oxidation; and (4) use operando infrared spectroelectrochemistry to observe reaction species at the electrode interface under applied voltage. This approach is expected to deliver improved catalyst concepts and reusable design rules that can support future CO2 conversion technologies aligned with EU climate goals.

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

Activities in this period built the scientific foundation needed to create durable COF electrocatalysts and to understand how they work while the reaction is running.
Work started with synthetic screening toward the planned porphyrin COFs with carbon–carbon double-bond (vinylene) linkages. As expected for this type of bond formation, achieving high crystallinity required longer optimization because the reaction is less reversible and very sensitive to small changes in conditions. To keep progress moving while vinylene optimization continues, a crystalline COF platform was prepared and used to develop a new step-by-step chemical route for framework upgrading and pore design. First, the framework bonds were chemically strengthened by converting imine linkages into reduced linkages. Next, the COF was given a reactive “handle” (a terminal alkyne), which allowed modular click chemistry to attach a protected guanidinium group inside the framework. This created a practical way to tune the pore environment in a controlled manner.
A major achievement of this period is that the project moved beyond “making a modified COF” to building a controlled and measurable chemistry platform. The amount of functional group introduced into the framework was quantified using a calibrated infrared method, so the modification level is known and can be compared across samples.
Separately, the parent COF platform was also used to build the mechanistic capability needed for catalyst design. Operando and in situ spectroelectrochemical methods were implemented to detect reaction species formed at the electrode interface while voltage is applied, using infrared spectroelectrochemistry (including surface-sensitive infrared measurements) and complementary electron paramagnetic resonance spectroelectrochemistry where relevant. These methods allow identification of key intermediates and provide direct evidence to connect electrode behavior with chemical changes during operation.
Overall, the project delivered: (1) a practical new chemistry route to strengthen and functionalize COFs with measurable control, and (2) an operando mechanistic toolkit that can reveal intermediates on the COF electrode interface under working conditions. Together, these outputs support the next steps of completing the targeted porphyrin COFs and building clear structure–function understanding for carbon dioxide conversion.

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)

The results achieved so far can be summarized as follows:
- Establishment of a reliable and reproducible synthetic route for covalent organic frameworks.
- Development of a stepwise post-synthetic modification strategy that reinforces the framework stability while introducing pore functionalities in a controlled and tunable manner.
- Quantitative determination of functional group incorporation, including evaluation of the efficiency of each individual reaction step.
- Implementation of an operando spectroelectrochemical platform enabling detection of chemical species formed at the COF electrode interface under applied potential.

These results are expected, in the longer term, to support the development of more durable COF-based catalyst designs for carbon dioxide conversion and to establish clearer correlations between framework structure, local chemical environment, reaction intermediates, and catalytic performance. In this way, the project contributes to shifting the field from empirical trial-and-error screening toward transferable, evidence-based design rules that can be adopted and further developed by other research groups.

To ensure further uptake and maximize impact, several key steps are required: (i) completion and optimization of the targeted vinylene-linked porphyrin COFs; (ii) generation of comprehensive benchmark datasets covering activity, selectivity, stability, and durability; (iii) validation of performance under more practically relevant electrochemical conditions and extended operating times; (iv) improvement of reproducibility at larger synthesis scale; and (v) once a clear enhancement in carbon dioxide affinity and catalytic performance is demonstrated for the functionalized materials, assessment of intellectual property protection in collaboration with the Knowledge and Technology Transfer unit, alongside identification of appropriate pathways for further development, scale-up, and potential demonstration.