Electron structure effects of S-doped In2O3 flowers on NO2 sensitivity

•S-doped In2O3 flowers were successfully prepared by microwave-assisted hydrothermal process and annealing.•Compared with conventional nanoflower materials, S-In2O3 flowers exhibit a low operating temperature of 118 °C and a high sensitivity response of 250 at 10 ppm NO2.•The gas-sensitive enhancement model of the electron structure effect was developed, and the validity of the model was verified by experiments and calculations.•The proposed method is low-cost and fast to synthesize, and these advantages are used to make low-temperature high-performance gas sensors.