Sensors and Actuators B-chemical | 2019
High acetone sensitive and reversible P- to N-type switching NO2 sensing properties of Pt@Ga-ZnO core-shell nanoparticles
Abstract
Abstract The typical core-shell Pt@ZnO, 1\u2009mol% Ga doped Pt@ZnO and 2\u2009mol% Ga doped Pt@ZnO nanoparticles were synthesized and utilized in acetone and NO2 sensing. Among those nanoparticles, 1\u2009mol% Ga doped Pt@ZnO based sensor presents excellent acetone sensitive and interesting reversible switching from P- to N-type NO2 sensing. The response of the 1\u2009mol% Ga doped Pt@ZnO based sensor to 50\u2009ppm acetone is as high as 296, and the detecting concentration limit to acetone and NO2 is as low as 10\u2009ppb and 20\u2009ppb. The analogical binary p-n transition phase diagram was established to understand the NO2-sensing reversible switching as a function of operating temperature (T) and NO2 gas concentration (C). The role of Ga doping in enhancing the sensing property and the mechanism of NO2 p–n sensing transition is elaborated. In conclusion, the doping of Ga into core-shell Pt@ZnO was proved to be a feasible method for fabricating acetone and NO2 sensor, with high sensitivity and selectivity.