NO2 Sensing Properties of Cr2WO6 Gas Sensor in Air and N2 Atmospheres

Abstract

Gas sensors were fabricated from Cr 2 WO 6 nanoparticles for NO 2 detection. Low dimensional materials Cr 2 WO 6 were prepared by a wet chemistry method followed by hydrothermal treatment. The morphology of the nanoparticles and their sensing properties to NO 2 were investigated in both dry and humid conditions. Additionally, the sensing response was also characterized in a non-oxygen condition. It was concluded that the sensor responses in N 2 conditions were higher than that in air conditions at 200 • C. Moreover, the sensing characteristics were inhibited by water vapor at 200 • C. The oxygen adsorption behavior was also investigated to verify the basic sensing mechanism of Cr 2 WO 6 in the absence and presence of NO 2 and water vapor separately. Based on the power law response, it was indicated that both NO 2 and water vapor have a strong adsorption ability than oxygen ions of Cr 2 WO 6 sensors.

2D Palladium Sulphate for Visible‐Light‐Driven Optoelectronic Reversible Gas Sensing at Room Temperature

“…As shown in Figure SI‐7, Supporting Information, the response factor was dropped from 3.19 at the dry condition to 3.1 and 2.9 for 30% RH and 50% RH, respectively, possibly due to the adsorption of water vapor as electron donors upon the PdSO 4 surface. [ 74,75 ] However, such an influence of humidity on the material is insignificant considering its negligible degradation of sensing performance.…”

Flower-like Hydroxyfluoride-Sensing Platform toward NO2 Detection

“…25,26 Because NO 2 and O 2 have the same adsorption sites on the surface of gas-sensing materials, the surface adsorption oxygen will have an adverse effect on NO 2 sensing. For example, Wu and his group 27 discovered the significantly improved sensitivity of Cr 2 WO 6 to NO 2 when N 2 rather than air was used as the environmental atmosphere. Moreover, NO 2 with high concentration may react with oxygen ions on the surface and lead to the p−n transition, thereby affecting its test range.…”

“…Because NO 2 and O 2 have the same adsorption sites on the surface of gas-sensing materials, the surface adsorption oxygen will have an adverse effect on NO 2 sensing. For example, Wu and his group discovered the significantly improved sensitivity of Cr 2 WO 6 to NO 2 when N 2 rather than air was used as the environmental atmosphere. Moreover, NO 2 with high concentration may react with oxygen ions on the surface and lead to the p–n transition, thereby affecting its test range. − In order to find better candidates for efficient NO 2 gas sensing, materials for other fields, like energy storage, catalysis, etc., − have been studied, such as metal sulfides (MoS 2 , and ZnS , ) and metal salts (ZnSnO 3 , and ZnTiO 3 ) and so on.…”