论文部分内容阅读
The PdCl_2 was mixed with nanocrystalline powders LaFeO_3 and subsequently followed by an annealing of 800 ℃. PdO phase was formed and almost distributed uniformly on the surface of LaFeO_3 nano-particles. With an increase of PdO amounts in composite powders, sensing sensitivity Rg/Ra to low concentration acetone or ethanol for Pd doped LaFeO_3 sensors increased at first, underwent the maximum with 2 wt.% PdCl_2 dopant, and then doped again. Interestingly, appropriate Pd doping in LaFeO_3 changed the selectivity behavior of gas sensing. LaFeO_3 sensor showed good selectivity to ethanol, but 2 wt.% Pd doped LaFeO_3 sensor showed good selectivity to acetone. The sensitivity for LaFeO_3 at 200 ℃ was 1.32 to 1 ppm ethanol, and 1.19 to 1 ppm acetone. Whereas the sensitivity for 2 wt.% Pd doped LaFeO_3 at 200 ℃ was 1.53 to 1 ppm ethanol, and 1.9 to 1 ppm acetone. The 2 wt.% Pd doped LaFeO_3 sensor 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 LaFeO_3 sensor is a new promising sensing candidate for detecting low concentration acetone.
PdO phase was formed and almost distributed uniformly on the surface of LaFeO_3 nano-particles. With an increase of PdO amounts in composite powders, sensing sensitivity Rg / Ra % PdCl_2 dopant, and then doped again. Interestingly, appropriate Pd doping in LaFeO_3 changed the selectivity behavior of gas sensing. LaFeO_3 sensor showed good The sensitivity for LaFeO_3 at 200 ℃ was 1.32 to 1 ppm ethanol, and 1.19 to 1 ppm acetone. Whereas the sensitivity for 2 wt.% Pd doped LaFeO_3 sensor showed good selectivity to acetone. LaFeO_3 at 200 ℃ was 1.53 to 1 ppm ethanol and 1.9 to 1 ppm acetone. The 2 wt.% Pd doped LaFeO_3 sensor at 200 ℃ showed very short response time (4 s) and recovery time (2 s) to 1 ppm acetone g as, respectively. Such results showed that 2 wt.% Pd doped LaFeO_3 sensor is a new promising sensing candidate for detecting low concentration acetone.