Ultrahigh methane sensing properties based on Ni-doped hierarchical porous In2O3 microspheres at low temperature

Abstract

Improving the methane (CH4) sensing characteristics of metal oxide semiconductors is a vital research issue. Herein, we reported the synthesis of porous Ni-doped In2O3 microspheres through an effective solvothermal strategy. The composition and structure of the as-prepared samples as well as the CH4 sensing properties were systematically characterized and investigated. The results demonstrate that Ni-doped In2O3 microspheres possess suitable pore sizes, small particle sizes and oxygen-enriched defects. Compared to bare In2O3 sensor, the sensor based on 5.0 mol% Ni-doped In2O3 (NIO-5.0) shows enhanced response (72.727) to 200 ppm CH4 at relatively low operating temperature (140 °C). Meanwhile, it also displays good selectivity, superior repeatability and long-term stability. The enhanced CH4-sensing performance could be mainly attributed to the stable porous structure and the abundant oxygen vacancy defects induced by Ni doping. Significantly, this work provides a great application prospect of Ni-doped In2O3 porous microspheres for low-temperature and high-response CH4 detection.