Adsorption and sensing mechanism of Pt-In2O3 sensor for NOx detection in thermal power plants
Thermal power generation produces NOx,which can cause serious harm to the ecological environment and public health.At present,the NOx detection of the thermal power plants in China mainly uses non-dispersive infrared technology and chemiluminescence technology,which need to manually collect the sample gas of the flue,which is a cumbersome step and cannot realize the accurate detection of NOx.The semi-conducting gas sensors have the advantages of small size,fast response and low cost,which are widely used for the detection of the gaseous pollutants.In this paper,the intrinsic In2O3 and Pt-In2O3 gas-sensitive materials were prepared by hydrothermal method.Based on the constructed trace gas-sensitive gas test platform,the concentration response and response-recovery time of In2O3-based sensors for NO and NO2were tested.The results show that the response values of the Pt-In2O3 sensor to 30 ppm NO2 and NO are 7.7 and 10.3,respectively,and the response recovery times are 23 s/41 s and 18 s/46 s,respectively,which are able to meet the requirements for NOxdetection in the thermal power plants.In addition,the adsorption energy and density of states of each adsorption model were calculated based on the density functional theory to reveal its gas-sensing mechanism.The analytical results show that Pt-In2 O3 exhibits strong chemisorption of NO(-1.55 eV)and NO2(-0.92 eV),which is consistent with the macroscopic experiment results.Therefore,the Pt-In2O3 sensor can realize NOx gas detection in the thermal power plants.
thermal power plantNOx gashydrothermal methodPt-In2O3gas-sensing mechanism
万方数据
