Sensing performances to low concentration acetone for palladium doped LaFeO3 sensors

The PdCl2was mixed with nanocrystalline powders LaFeO3and subsequently followed by an annealing of 800 ℃. PdO phase was formed and almost distributed uniformly on the surface of LaFeO3nano-particles. With an increase of PdO amounts in composite powders, sensing sensitivity Rg/Ra to low concentration acetone or ethanol for Pd doped LaFeO3sensors increased at first, underwent the maximum with 2 wt.% PdCl2dopant, and then doped again. Interestingly, appropriate Pd doping in LaFeO3changed the selectivity behavior of gas sensing. LaFeO3sensor showed good selectivity to ethanol, but 2 wt.% Pd doped LaFeO3sensor showed good selectivity to acetone. The sensitivity for LaFeO3at 200 ℃ was 1.32 to 1 ppm ethanol, and 1.19 to 1 ppm acetone. Whereas the sensitivity for 2 wt.% Pd doped LaFeO3at 200 ℃ was 1.53 to 1 ppm ethanol, and 1.9 to 1 ppm acetone. The 2 wt.% Pd doped LaFeO3sensor at 200 ℃ showed very short response time(4 s) and recovery time(2 s) to 1 ppm acetone gas, respectively. Such results showed that 2 wt.% Pd doped LaFeO3sensor is a new promising sensing candidate for detecting low concentration acetone.