Investigation on No2 Gas Sensing Performance of Au- Loaded Polypyrrole

Au atom-loaded Polypyrrole (PPy) is proposed to improve the Nitrogen dioxide (NO2) sensitivity of the organic PPy sensor at room temperature (RT) in this work. Au nanoparticles loaded with PPy nanomaterials are synthesized by water bath and Au nanoparticles uniformly adhere to PPy nanosheets to form Au@PPy composite structure. Au@PPy sensor shows magnificent NO2 gas sensing performance due to the loading of Au atom. The gas sensing response of Au@PPy sensor is 61 %, 2 times more than that of the PPy sensor (21 %) to NO2 30 ppm. The anti-interference capability of Au@PPy sensor has been significantly improved. The response of Au@PPy sensor to the main interfering gas of ammonia is 32 %, 0.5 times more than that of PPy. The adsorption energy and electron transfer of Au@PPy to NO2 molecules were calculated based on Density Functional Theory (DFT). The adsorption energy of Au@PPy to NO2 is 1.21 e, 1.7 times that of PPy and the electron transfer from Au@PPy to NO2 is 0.59 e, which is about 7.4 times that of PPy. The outstanding sensing performance can be attributed to the increase in the carrier concentration and the surface-active sites due to Au atom loading. This strategy of noble metal loading is beneficial for the development of gas sensors.