Significant progress was made in Work Package 1, where high-throughput simulations screened large databases of MOFs (Metal–Organic Frameworks) and zeolites for adsorption of VOCs (Volatile Organic Compounds) such as acetone. Materials with optimal properties were identified using metrics like Henry’s constant and adsorption enthalpy. Critical structural factors, such as hydrophobicity and confinement, were identified, resulting in the creation of a refined database and selecting promising candidates for further validation. These findings were shared with the consortium for experimental synthesis and testing.
Experimental adsorption tests focused on validating the computational predictions for materials like MOFs and zeolites. For example, in situ FTIR (Fourier Transform Infrared Spectroscopy) studies revealed that specific materials exhibit chemisorption or physisorption characteristics, depending on their structural features. Testing has begun to evaluate these behaviours under realistic indoor air conditions, providing critical insights for refining material selection.
Advancements include the successful synthesis of tailored MOFs (e.g. CAU-10-CH3, CAU-21) and zeolites with enhanced adsorption properties for acetone. The synthesis process utilized innovative techniques like microwave-assisted methods. The materials were optimized for integration into sensor devices by modifying pore size, linker functionalization, and hydrophobicity, improving their selectivity and capacity for mixed-component adsorption.
Efforts under Work Package 5 include fabricating sensors using MOFs and zeolites. Composite materials, such as ZIF (Zeolitic Imidazolate Framework)-coated ZnO, were prepared and characterized for their integration into sensing layers. Real-world testing strategies have been outlined to benchmark sensor performance under varying humidity and VOC concentrations, ensuring robustness and reliability.
In this stage, the development of signal-processing methods focused on parameter extraction from the raw sensor signal. Initial datasets from experimental setups demonstrated the potential for accurately identifying VOC mixtures using advanced data processing techniques like non-negative least squares and exponential decomposition methods. These methods also addressed interferences from environmental factors such as temperature and humidity.
ZIF-71 coated CuO: Al based gas sensor has been developed which exhibits remarkable detection of n-butanol and hydrogen at 200 and 250℃, respectively. The fabricated sensor shows ~4 times more selectivity for n-butanol than hydrogen and ~5 times than acetone. The fabricated sensor was tested for against relative humidity (RH10% and RH 50%). The results obtained shows good temporal stability. ZIF-8 coated CuO: Al gas sensor has been developed which exhibits good detection for hydrogen in the temperature range 250-350℃. Among tested VOCs (n-butanol, acetone, ethanol, 2-prpanol), it exhibits good selectivity for 2-propanol and n-butanol as compared to ethanol and acetone in the temperature range 250-350℃. It retains the remarkable hydrogen sensing performance at higher RH 50% at all tested concentrations 10 ppm, 50 ppm, 100 ppm, and 1000 ppm.
