Advanced Co Sensing Capabilities of Pt/Sno2/Nio Sensors for High-Humidity Applications

Abstract

Aimed at realizing the sensors capable of functioning effectively in high-humidity environments, the Pt/SnO2/NiO ternary composite materials featuring noble metal and p-n heterojunction structures was synthesized. The dispersion of SnO2 and Pt nanoparticles on NiO nanosheets was found to be excellent, resulting in a substantial increase in specific surface area compared to pure NiO materials. The CO sensitivity tests revealed that, in contrast to pure NiO sensors (with an optimal operating temperature of 290°C), Pt/SnO2/NiO ternary composites exhibited an optimal operating temperature (OOT) of 270°C for CO detection at a relative humidity of 22%. At this OOT, Pt/SnO2/NiO sensors consistently displayed high responsiveness, good selectivity, and rapid response-recovery times. Furthermore, the sensors' responses to CO under different humidity conditions were investigated. The results demonstrated that Pt/SnO2/NiO sensors exhibited minimal variation in their response to CO gas across a range of relative humidity levels (from 22% to 91%) at 270°C. These results highlight that the enhancement of CO gas sensitivity in the sensors primarily results from the high catalytic activity of noble metal Pt and the p-n heterojunction interaction.

Keywords: noble metal, p-n heterojunction, Ternary composite materials, CO sensors, Relative humidity