Metal-organic framework-derived Cr-doped hollow In2O3 nanoboxes with excellent gas-sensing performance toward ammonia

Abstract Transition metal ions doping is an effective method to improve the gas sensing performance of metal oxide semiconductors. Herein, we report the synthesis of Cr-doped In2O3 samples by calcining metal-organic frameworks (MOFs)-precursors prepared by a simple oil bath method. The experimental characterization results show that the as-prepared samples exhibit uniform hollow nanoboxes with large specific surface areas. Through comparison, the 0.5 wt% Cr-doped In2O3 sample with complete and regular morphology was selected for a series of gas-sensitive performance tests. The results show that the sensor has good detection performance for ammonia (NH3). Gas-sensing tests revealed that the sensor exhibited excellent sensing performance towards NH3 with low operating temperature (140 °C), high selectivity, good repeatability, relatively high response, low detection concentration (~ 1 ppm), and short response time (~ 1 s). The generation of lattice defects and the increased conductivity after doping are the reasons for the excellent performance of the sensor. This provides a new strategy for the research and preparation of high performance gas sensors.