Articles | Volume 3, issue 2
J. Sens. Sens. Syst., 3, 273–280, 2014

Special issue: Advanced functional materials for environmental monitoring...

J. Sens. Sens. Syst., 3, 273–280, 2014

Regular research article 30 Oct 2014

Regular research article | 30 Oct 2014

Catalytic and thermal characterisations of nanosized PdPt / Al2O3 for hydrogen detection

T. Mazingue1, M. Lomello-Tafin1, M. Passard1, C. Hernandez-Rodriguez1, L. Goujon1, J.-L. Rousset2, F. Morfin2, and J.-F. Laithier3 T. Mazingue et al.
  • 1Univ. Savoie, SYMME, 74000 Annecy, France
  • 2Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON, CNRS – University of Lyon), 2 avenue Albert Einstein, 69626 Villeurbanne CEDEX, France
  • 3Comelec SA, Rue de la Paix 129 – 2301 La Chaux-de-Fonds, Switzerland

Abstract. Palladium platinum (PdPt) has been intensively studied these last decades due to high conversion rate in hydrogen oxidation at room temperature with significant exothermic effects. These remarkable properties have been studied by measuring the temperature variations of alumina (Al2O3) supported nanosized PdPt nanoparticles exposed to different hydrogen concentrations in dry air. This catalyst is expected to be used as a sensing material for stable and reversible ultrasensitive hydrogen sensors working at room temperature (low power consumption). Structural and gas sensing characterisations and catalytic activity of PdPt / Al2O3 systems synthesised by co-impregnation will be presented. Catalytic characterisations show that the system is already active at room temperature and that this activity sharply increases with rise in temperature. Moreover, the increase of the PdPt proportion in the co-impregnation process improves the activity, and very high conversion can be reached even at room temperature. The thermal response (about 3 °C) of only 1 mg of PdPt / Al2O3 is reversible, and the time response is about 5 s. The integration of PdPt / Al2O3 powder on a flat substrate has been realised by the deposition onto the powder of a thin porous hydrophobic layer of parylene. The possibility of using PdPt in gas sensors will be discussed.

Short summary
In this article, we propose detecting hydrogen (H2) traces at room temperature with nanostructured PdPt/Al2O3 catalysts. We measure the temperature rise during the exothermic oxidation of H2 by the catalyst. An appropriate formulation of about 1 mg of PdPt/Al2O3 leads to reversible thermal responses of 3°C in only 5 s. We show that this active material is a promising candidate for autonomous and reversible passive transducers for H2 sensors working at room temperature in explosive atmospheres.