Ultrasensitive gas sensor based on nanocube In2O3-CNH composite at low operating temperature

A facile solvothermal route prepared In 2 O 3 /CNH nanocomposites with different CNH concentrations. All nanocomposites' structural and morphological properties were investigated by XRD, FESEM, TEM, XPS, and BET. The H 2 S sensing performance of the sensors based on them was tested, operated between 40 °C and 300 °C. The results showed that the optimal composition is In 2 O 3 /CNH (2 wt%) with a sensor signal to 2 ppm H 2 S, at an operating temperature of 70 °C, of almost 3000. The sensors demonstrated excellent selectivity, low impact of humidity and good reproducibility and stability. The superior sensor performance is related to the p-n junction formation between the CNH and In 2 O 3 , which determines the increase of the surface band bending and the sensor response. The gas sensing mechanism is thoroughly discussed, and the In 2 O 3 /CNH nanocomposite sensor can be considered an ideal candidate for high-performance detection of H 2 S with low-power consumption. • Carbon Nanohorn (CNH) and In 2 O 3 composite are applied to gas sensor for the first time. • In 2 O 3 /CNH (2 wt%) based sensors shows ultrahigh gas sensing performances toward H 2 S, with the sensitivity of 2906 to 2 ppm. • In 2 O 3 /CNH (2 wt%) based sensors operating temperature as low as 70 °C, and the detection limit can be reduced to 50 ppb.