Cubic Bixbyite In ₂ O ₃ Nanoparticles Enhanced B Phase VO ₂ Nanorods Room Temperature Sensing Performance for NH ₃ Gas Detection

c-In2O3 nanoparticles modified VO2(B) nanorods heterojunction composite structure was proposed to enhance the NH3 sensing performance at room temperature (25 °C). The c-In2O3 /VO2(B) heterojunction composite structure was prepared by the combination method of chemical precipitation and annealing. The effect of NaOH solution concentration in chemical precipitation on the composite structure and sensing performance was explored. The c-In2O3 nanoparticles with uniform size distributed unevenly on the VO2(B) nanorod surface and formed a heterojunction composite structure at the NaOH solution concentration of 1.25 M. The c-In2O3/VO2(B) composite structure based sensor exhibited an excellent response of 232 to 100 ppm of NH3 at room temperature, and also exhibited good selectivity and long-term stability. This outstanding performance can be attributed to the heterojunction effect, enhanced catalytic and oxygen absorption effect, and defect surface of c-In2O3 nanoparticles. This result will be helpful for the fabrication of high performance room temperature NH3 sensors.