Monitoring changes in gas composition in the environment is becoming increasingly important for future industrial production and daily activities. The effectiveness of this monitoring largely depends on the reliability and performance of gas sensors. At present, chemical resistance gas sensors mainly based on metal oxides such as ZnO, SnO2, and WO3 have been widely used in various gas monitoring scenarios due to their cost-effectiveness and ease of preparation. However, traditional metal oxide semiconductor (MOS) sensors face challenges related to low selectivity, high operating temperature, and limited long-term stability. On the contrary, electrochemical gas sensors have the advantages of low energy consumption (can operate at room temperature) and high selectivity. However, their widespread adoption is still limited, mainly due to the high production costs associated with noble metal catalysts such as carbon supported platinum (Pt/C), as well as issues related to the long-term stability of traditional platinum (Pt) based gas sensors. There is an urgent need to develop cost-effective and durable catalytic materials with special sensitivity to target gases.
Nitrogen dioxide (NO2) is an important air pollutant that mainly comes from vehicle engines and industrial activities, posing risks to the environment and health. Regulatory intervention aims to reduce anthropogenic nitrogen oxide emissions. The current NO2 detection methods utilize gas chromatography-mass spectrometry, infrared absorption sensors, and chemical resistance gas sensors. However, challenges such as equipment cost, testing complexity, and high operating temperatures still exist. Although the titanium carbide/L-glutamic acid (Ti3C2Tx/γ - PGA) chemical resistance gas sensor exhibits better response than Ti3C2Tx, stability remains an issue. Similarly, the graded C-MoS2 chemical resistance gas sensor exhibits excellent performance at low NO2 concentrations (5 ppb), but with a slower recovery time (50 minutes). Therefore, it is crucial to develop electrochemical sensors with higher sensitivity, stability, and NO2 detection selectivity.
1.This work introduces a novel and cost-effective electrochemical sensor, which uses nitrogen doped indium oxide In2O3 − xN2x/3Vx/3 (0.01 ≤ x ≤ 0.14) synthesized through different nitriding times.
2.The optimized In2O3 N-40 minute sensor exhibits a significant response current of 771 nA to 10 ppm nitrogen dioxide (NO2) at ambient temperature, with excellent long-term stability (over 30 days) and fast response/recovery time (5/16 seconds).
3.Compared with Pt/C sensors, its response time and recovery time have been shortened by 84% and 67%, respectively. After one month, its performance remains at 98%, while Pt/C's performance is 68%.
Source: Sensor Expert Network