Enhancement of La0.8Sr0.2MnO3-based amperometric total NOX sensor via modification with Pt nanoparticles

Pt nanoparticle (PtNP)-modified La0.8Sr0.2MnO3 (LSM)-sensing electrodes (SE) were developed successfully by the impregnation method for amperometric total NOX (NO and NO2) sensors. The structure, morphology, and surface valence state of SE were characterized by thermogravimetry (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results showed that all SEs of the sensors were uniformly modified with PtNPs; interestingly, the size of the PtNPs increased with an increase in the modified content. Compared with pure LSM, the sensor based on 0.50 vol% Pt/LSM exhibited enhanced gas-sensing properties toward total NOX. The sensitivity improved from − 9.04 to − 18.7 μA/decade in the NOX, ranging from 50 ppm to 800 ppm. Moreover, the sensor maintained a 94% response signal after a long-term stability test, showing a stable response during the long-term thermal cycling test towards total NOX. Meanwhile, the sensor exhibited markable selectivity and consistency. The catalytic effect of Pt nanoparticles was believed to be the main reason for the enhancement of gas-sensing characteristics.