Methane Combustion Using Pd Deposited on CeO-MnO/La-AlO Pellistors.

Pd deposited on CeO-MnO/La-AlO has been prepared as a sensitive material for methane (CH) detection. The effect of different amounts (1.25%, 2.5% and 5%) of Pd loading has been investigated. The as prepared materials were deposited on Pt microcoils using a drop-coating method, as a way of developing pellistors operated using a Wheatstone bridge configuration. By spanning the operating temperature range between 300 °C and 550 °C, we established the linearity region as well as the maximum sensitivity towards 4900 ppm of CH. By making use of the sigmoid dependence of the output voltage signal from the Wheatstone bridge, the gas surface reaction and diffusion phenomena have been decoupled. The pellistor with 5% Pd deposited on CeO-MnO/La-AlO exhibited the highest selective-sensitivity in the benefit of CH detection against threshold limits of carbon monoxide (CO), sulfur dioxide (SO) and hydrogen sulfide (HS). Accordingly, adjusting the percent of Pd makes the preparation strategies of pellistors good candidates towards CH detection.