Influence of surface Pd doping on gas sensing characteristics of SnO2 thin films deposited by spray pirolysis

Abstract In this article the analysis of steady state and transient gas sensing characteristics of undoped and Pd surface doped SnO2 films, deposited by spray pyrolysis, is described. The influence of parameters such as air humidity (2–50% RH), operation temperature (25–500 °C) and Pd surface concentration (0–1% ML Pd) on gas response to CO and H2 (0.1–0.5%), response time, shape of sensitivity S(T) curves and activation energy of τ(1/kT) dependencies are discussed. A mechanism based on a chemisorption model is proposed to explain how Pd influences the gas sensing characteristics of SnO2 films.