Cr 2 O 3  / Rgo Based Gas Sensor for N -Butanol with High Sensitivity and Fast Response

Abstract

The n-butanol is a toxic and hazardous compound, and prolonged exposure to the gas raises safety and health concerns. Addressing this issue, the development of high response, selectivity and stability of n-butanol gas sensing technologies is critical for environmental protection and human health. In this work, the gravity-induced sedimentation method is used to grow Cr2O3 nanoparticles on 2D RGO nanosheets via a low-cost hydrothermal method, inhibiting the agglomeration and stacking of Cr2O3 nanoparticles and promoting the formation of Cr2O3/RGO p-p heterojunctions that enhance the sensing performance of n-butanol at ppb-level concentrations. The structural characterization of the Cr2O3/RGO composites were discussed through SEM, TEM, XRD, Raman, BET and XPS. In addition, the Cr2O3/RGO (RGO/Wtotality=2.9 wt%) based sensor maintained a high response of 121.2 towards 100 ppm n-butanol gas with a fast response time of 150 s at 160 ℃ and a theoretical limit of detection of about 8.6 ppb, meanwhile, the gas sensor has reliable repeatability. Finally, the sensitization mechanisms are discussed. The introduction of the 2D RGO nanosheets improves the reactive active sites and prevents the aggregation of Cr2O3 nanoparticles. The construction of Cr2O3/RGO p-p heterojunctions enable efficient electron transfer within the composites, and the modulation of the energy bands significantly enhances the ability of the Cr2O3/RGO composites surface to adsorb oxygen. There is no doubt that the scientific investigation of the present work will facilitate the potential application of ppb-level n-butanol detection.

Keywords: Hydrothermal method, p-p Cr2O3/RGO heterojunctions, RGO, theoretical limit