Construction of MOF-derived In2O3/g-C3N4/rGO nanostructures to enhance NOx gas-sensitive properties at room temperature

Abstract

In this paper, In2O3/g-C3N4/rGO as a novel high-performance NOx gas sensor is successfully prepared by the solvothermal method. The gas sensing performance of In2O3/g-C3N4/rGO nanocomposites toward NOx is significantly enhanced, with a response (2040) to 100 ppm NOx about seven times more than In2O3/g-C3N4. Meanwhile, In2O3/g-C3N4/rGO has a faster reaction/recovery time (96/52 s) than In2O3/g-C3N4 (700/81 s) and exhibits good selectivity, reproducibility and low detection limits. The adsorption process of NOx on the surface of the In2O3/g-C3N4/rGO is studied by Diffuse Reflectance Infrared Fourier Transformed (DRIFT). The gas-sensitive properties of In2O3/g-C3N4/rGO are enhanced because of the heterogeneous structure formed among the MOF-derived In2O3 nanotubes, g-C3N4 and rGO nanosheets and have a large specific surface area. The good electron mobility of rGO, the sensitizing effect of g-C3N4 and the unique structure of the MOF-derived In2O3 are also advantageous for enhancing gas sensing performance. Therefore, In2O3/g-C3N4/rGO ternary nanocomposites are excellent candidates for NOx gas sensors.