Amperometric hydrocarbon sensor using La(Sr)Ga(Fe)O_3 solid electrolyte for monitoring in exhaust gas

摘要

Emission of hydrocarbon at low temperature, especially in the cold start condition of the automobile engine, has attracted attention these days. For the first time an electrochemical sensor based on LaGaO_3 with iron doping was demonstrated to have very high sensitivity to propene (C_3H_6) at low temperature (423-573 K). In the amperometric mode, the output current signal was found to increase linearly with the C_3H_6 concentration (500-2000 ppm) in logarithm scale. Effect of iron doping at the gallium site was found to influence the sensing properties greatly and the electrolyte composition La_(0.7)Sr_(0.3)Ga_(0.7)Fe_(0.3)O_3 showed the highest sensitivity of 976 μA/decade at 473 K. The sensors were fast, reproducible and highly selective to hydrocarbons.