A low temperature, highly sensitive and fast response toluene gas sensor based on In(III)-SnO2 loaded cubic mesoporous graphitic carbon nitride

Abstract

Abstract Low temperature gas sensors for monitoring low ppm volatile organic compounds (VOCs) in indoor climate have critical advantages in designing portable sensing devices. Herein, a highly sensitive as well as fast response In(III)-SnO2 loaded cubic mesoporous mpg-CN (commonly known as g-C3N4) based toluene gas sensor has been fabricated through template inversion of KIT-6. When exposed to a variety of test VOCs at 200 °C, the In(III)-SnO2/mpg-CN (1% In) showed a highly selective response (Ra/Rg = 61.4) and fast reversible response/recovery (4/2 s) to 50 ppm toluene gas. The sensor was also able to selectively detect 50 ppm (R = 2.4) and 100 ppm (R = 3.6) toluene gas at 90 °C. Compared to mesoporous In(III)-SnO2, the mpg-CN supported In(III)-SnO2 nanocomposite shows ∼2 fold increase in response to toluene gas while reducing the optimized operating temperature by 50 °C. The significant enhancement in sensitivity and lowering down of optimized operating temperature is attributed to the higher surface area, easily accessible mesopore channels of 3D mesoporous cubic structure and suitable heterojunction formation by the semiconducting In(III)-SnO2/mpg-CN nanocomposite. The findings reported in this study shows promising glimpse for designing a novel strategy to the development of ultrasensitive VOCs sensors working at low operating temperature.