Defects-enriched two-dimensional ultrathin g-C3N4/In2O3 nanoparticles for effective NO2 detection at room temperature

Rational integration of ultrathin two-dimensional(2D) graphitic carbon nitride(g-C3N4) nanosheets and indium oxide(In2O3) nanoparticles was implemented by hydrothermal and calcination. The optimized composites demonstrated an outstanding NO2 response of 1470 (5 ppm) and short response/recovery time (67/46 s). Moreover, the prepared composites displayed excellent reproducibility, low detection limit (18 ppb), and satisfactory selectivity to NO2 at room temperature (RT). The gas sensing mechanism was also proposed and verified by the density functional theory calculation. The outstanding gas sensing properties might be due to the combination of heterojunction, enhanced specific surface, and enriched defects. This study gives a reference for designing sensing materials by forming heterojunctions between metal oxides and g-C3N4 for superior gas sensitivity and exploring the manufacture of advanced gas sensors.