05 - Potentialities of Metallophthalocyanines-Based Gas Sensors for Monocyclic Hydrocarbons Monitoring in Air

Fourth Scientific Meeting EuNetAir
2015-06-03 - 2015-06-05
Linkoping University, Linkoping, Sweden
Fourth Scientific Meeting EuNetAir
J. Brunet, A. Kumar, C. Varenne, A. Ndiaye, A. Pauly - Clermont Université, Université Blaise Pascal, Clermont-Ferrand, France
18 - 21


Focused on the development of chemical sensors dedicated to BTX measurements, our recent works have demonstrated the relevance of tetra-tert-butyl metallophthalocyanines (ttb-MPc) as sensitive material for this purpose. Taking into consideration the aromatic character of both the target gases and the sensing material, sorption mechanisms involve π-stacking interactions without charge transfer between gaseous molecules and phthalocyanine units. Because of the nature of interactions, acoustic transducer and more precisely quartz crystal microbalance were used. Studies achieved on different unsubstituted metallophthalocyanines have revealed the non-significant effects of the central metal atom on the sensor responses and the limited sensitivity towards the target gases. In contrast, the predominant role of electro-donor substituents like tert-butyl groups grafted at the periphery of phthalocyanine macrocycle on sensing characteristics has been clearly established. A 6-time greater sensitivity to BTX was obtained for ttb-MPc as compared to unsubstituted metallophthalocyanines. Response and recovery times at room temperature close to 3 minutes were measured. Sensing performances enhancement observed for ttb-MPc as compared to unsubstituted phthalocyanines are strongly linked to the structure and the morphology of the thin layers as highlighted by SEM characterization. If ttb-MPc-based QCM sensors are insensitive to H2S, CO and NO2, the discrimination between benzene, toluene and xylene remains a challenge. Ongoing research on this problematic will be finally discussed.