Investigation of catalytic hydrogen sensors with platinum group catalysts

Abstract

Environmental deterioration and limited resources of hydrocarbons push the development of alternative power sources. One of the most promising energy carriers is hydrogen. However, handling hydrogen is more hazardous than the use of hydrocarbons because it has a significantly wider flammable range. Thus the development of new sensors for preventing hydrogen leakage is the actual task of modern materials science and chemical engineering. In this work, the response of catalytic sensors to hydrogen with different catalysts of platinum group (Pt, Pd, Ir, Rh, Pt + Pd, Pt + Pd + Rh, Pt + Pd + Ir) in the pre-explosion concentration range is studied. Temperature dependencies of sensitivity are discussed. A hysteresis in sensor response is observed during the cycling of the supply voltage. This phenomenon can be explained by partial transformation of platinum group metal oxides into metallic phase at a temperature of more than 500 °C and reverse metal oxidation at temperatures less than 400 °C. It has been shown that the sensors with catalysts containing Ir and Rh demonstrate more preferable characteristics for practical applications.