Development of Potentiometric Sensors for C?H? Detection.

ABSTRACT: Gas exhaust emissions in vehicles are increasingly restrictive in EU and USA. Diesel engines are particularly affected by limitation in hydrocarbons and NOx concentrations. This work presents a screening of working electrode materials to develop a potentiometric sensor, with the most promising material to detect being C?H? at 550 °C. The device consists of a dense 8YSZ (8 mol% Y?O? stabilized ZrO?) disk as oxide-ion conducting electrolyte, whereas platinum is screen-printed in the back face as reference electrode. As working electrode, several materials such as Fe_0.7Cr_1.3O?, ZnCr?O?, Fe?NiO?, La_0.8Sr_0.2CrO_3-? (LSC), La_0.8Sr_0.2MnO? (LSM), and NiO+5%wt Au were tested to detect C?H?. Sensor voltage was measured for several concentrations of C?H? and CO as these are two of the major oxidizable compounds in a diesel exhaust gas. Fe_0.7Cr_1.3O? was selected as the most promising material because of its response to C?H? and CO. Not only is the response to the individual analytes important, but the C?H? cross-sensitivity toward CO is also important. Fe_0.7Cr_1.3O? showed a good performance to C?H?, with low cross-sensitivity to CO. In addition, when 0.16 ppm of phenanthrene is added, the sensor still has a slightly better response to C?H? than to CO. Nevertheless, the sensor exposure to high concentrations (>85 ppm) of polycyclic aromatic hydrocarbons led to signal saturation. On the other hand, the operation in wet conditions induces lower sensor sensitivity to C?H? and higher cross-sensitivity toward CO increase, i.e., the sensor response becomes similar for C?H? and CO.

SUBMITTER: Toldra-Reig F 

PROVIDER: S-EPMC6164524 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature