Periodic Reporting for period 1 - MOF-PEMs (Design Proton-Conducting Metal Organic Frameworks based membranes for Proton Exchange Membrane Fuel Cell Applications)
Reporting period: 2023-09-01 to 2025-09-30
The MOF-PEMs project addresses one of the key challenges in the transition toward clean energy — the development of efficient, durable, and environmentally friendly materials for proton-exchange membrane fuel cells (PEMFCs).
Conventional membranes such as Nafion rely on fluorinated polymers, which are expensive, environmentally persistent, and show performance loss under low humidity.
The project set out to design and synthesise a new generation of fluorine-free, intrinsically proton-conductive porous materials, known as Metal–Organic Frameworks (MOFs) and Covalent Organic Frameworks (COFs).
These materials combine the advantages of crystalline order, tunable porosity, and functional groups capable of conducting protons without the need for external dopants or additives.
Initially, the research focused on phosphonate linkers, which offer excellent chemical stability. However, due to synthesis difficulties, the strategy was adapted to functionalised carboxylate linkers, particularly BTC-NH2 and SSA (sulfosuccinic acid).
This change allowed for reproducible, green syntheses and led to the discovery of new classes of materials with intrinsic conductivity comparable to, or higher than, benchmark systems.
The main goal of MOF-PEMs is to contribute to the European Green Deal and the Clean Hydrogen Partnership by providing sustainable alternatives to fluorinated PEM materials.
Conventional membranes such as Nafion rely on fluorinated polymers, which are expensive, environmentally persistent, and show performance loss under low humidity.
The project set out to design and synthesise a new generation of fluorine-free, intrinsically proton-conductive porous materials, known as Metal–Organic Frameworks (MOFs) and Covalent Organic Frameworks (COFs).
These materials combine the advantages of crystalline order, tunable porosity, and functional groups capable of conducting protons without the need for external dopants or additives.
Initially, the research focused on phosphonate linkers, which offer excellent chemical stability. However, due to synthesis difficulties, the strategy was adapted to functionalised carboxylate linkers, particularly BTC-NH2 and SSA (sulfosuccinic acid).
This change allowed for reproducible, green syntheses and led to the discovery of new classes of materials with intrinsic conductivity comparable to, or higher than, benchmark systems.
The main goal of MOF-PEMs is to contribute to the European Green Deal and the Clean Hydrogen Partnership by providing sustainable alternatives to fluorinated PEM materials.
The project successfully synthesised and characterised 25 new porous materials:
-15 MOFs, including the IEF-37 series (bimetallic Ti/Ca and Ti/Mn systems), MOF-808-NH2, and the SSA family (Zr-SSA, Hf-SSA, MOF-808-SSA).
- 10 COFs, comprising the benzi-COFs and the patented IEP series (EP 25382749.7).
These frameworks exhibit high proton conductivities of 10-2- 10-4 S cm-1 achieved through functional groups such as –NH2, –SO3H and hydrazone bridges that promote intrinsic, long-term conduction. The most promising systems—Hf-SSA and sulfonated benzi-COFs are being planned to integrated into mixed-matrix membranes (MMMs) at UC3M (Madrid) for PEMFC testing.
All scientific objectives were met, exceeding initial targets.
In addition to clean-energy applications, several materials demonstrated potential for environmental remediation, including the capture of CO2 and SO2 (IEF-37 MOFs), and removal of PFAS contaminants from water (MOF-808-NH2 series), and efficient water-harvesting capability (IEF-37 MOFs).
These results highlight the versatility of the materials and their contribution to the EU’s Zero Pollution and Sustainability strategies. Key collaborations enhanced the project scope:
- ICGM Montpellier-CNRS (France): modelling and adsorption simulations;
- Rice University (USA): PFAS-removal testing;
- Oregon State University (USA): CO2 and H2O-sorption studies;
- UNAM (Mexico): SO2-capture and sensing.
-15 MOFs, including the IEF-37 series (bimetallic Ti/Ca and Ti/Mn systems), MOF-808-NH2, and the SSA family (Zr-SSA, Hf-SSA, MOF-808-SSA).
- 10 COFs, comprising the benzi-COFs and the patented IEP series (EP 25382749.7).
These frameworks exhibit high proton conductivities of 10-2- 10-4 S cm-1 achieved through functional groups such as –NH2, –SO3H and hydrazone bridges that promote intrinsic, long-term conduction. The most promising systems—Hf-SSA and sulfonated benzi-COFs are being planned to integrated into mixed-matrix membranes (MMMs) at UC3M (Madrid) for PEMFC testing.
All scientific objectives were met, exceeding initial targets.
In addition to clean-energy applications, several materials demonstrated potential for environmental remediation, including the capture of CO2 and SO2 (IEF-37 MOFs), and removal of PFAS contaminants from water (MOF-808-NH2 series), and efficient water-harvesting capability (IEF-37 MOFs).
These results highlight the versatility of the materials and their contribution to the EU’s Zero Pollution and Sustainability strategies. Key collaborations enhanced the project scope:
- ICGM Montpellier-CNRS (France): modelling and adsorption simulations;
- Rice University (USA): PFAS-removal testing;
- Oregon State University (USA): CO2 and H2O-sorption studies;
- UNAM (Mexico): SO2-capture and sensing.
MOF-PEMs established a new paradigm for intrinsic proton conduction in porous materials, where the transport pathway arises from permanent functional groups embedded within the framework. This differs from traditional extrinsic conductors that rely on added acids or dopants, improving both stability and durability.
Major advances include:
- First SSA-based MOFs synthesised in water with intrinsic conductivities around 10-3 S·cm-1.
- Sulfonated benzi-COFs reaching ≈10-2 S·cm-1 among the highest intrinsic proton conductive COFs.
- MOF-808-SSA, showing a three-orders-of-magnitude conductivity increase over its parent structure.
- The creation of IEP-COFs, a new hydrazone-linked gel family protected by European patent EP 25382749.7.
These results move the field beyond current benchmarks and open opportunities for future research in fuel-cell membranes, environmental remediation and advanced functional coatings.
Major advances include:
- First SSA-based MOFs synthesised in water with intrinsic conductivities around 10-3 S·cm-1.
- Sulfonated benzi-COFs reaching ≈10-2 S·cm-1 among the highest intrinsic proton conductive COFs.
- MOF-808-SSA, showing a three-orders-of-magnitude conductivity increase over its parent structure.
- The creation of IEP-COFs, a new hydrazone-linked gel family protected by European patent EP 25382749.7.
These results move the field beyond current benchmarks and open opportunities for future research in fuel-cell membranes, environmental remediation and advanced functional coatings.