Ppb-level fuel cell type NO2 sensor based on Nafion proton membrane and Au-Ni/CF sensitive electrode

The fuel cell type gas sensor has attracted wide attention due to its advantages of operating at room temperature, low power consumption and good stability. In this study, a new sensitive electrode material Au-Ni/CF was developed for the detection of NO 2 . Through XRD , SEM and TEM characterization, it has been demonstrated that the electrode material exhibits improved crystallinity after being sintered at high temperatures. This leads to a reduction in charge transfer impedance. Additionally, XPS testing and TEM characterization have confirmed that high temperature sintering results in the reduction of more metal elements, leading to an increase in the electrochemical surface area and effectively improving sensor sensitivity. Furthermore, adjusting the mass ratio of gold to nickel can alter the surface lattice arrangement and electronic structure of the electrode material, subsequently impacting its resistance and catalytic ability towards NO 2 , ultimately enhancing sensor sensitivity. The sensitivity of the sensor using Au 5 Ni 2 /CF as the electrode material for detecting 0.05–10 ppm NO 2 was found to be 47.88 nA/ppm with response and recovery times of 35 s and 25 s respectively when exposed to 2 ppm NO 2 . Furthermore, it exhibited good selectivity and stability, indicating promising potential for application in room temperature atmospheric environment monitoring.