Highly sensitive and ultra-fast gas sensor based on CeO2-loaded In2O3 hollow spheres for ppb-level hydrogen detection

H2 detection sensors based on pure and different contents of CeO2 (0.5 at%, 1 at%, 2 at%, 4 at%, 6 at%) loaded In2O3 hollow spheres were successfully fabricated. The crystal phase, morphology and chemical composition of the obtained CeO2-loaded In2O3 samples were analyzed by characteristic techniques. The gas sensing results showed that the CeO2-loaded In2O3 gas sensors exhibit enhanced H2 sensing performances compared with pure In2O3 at optimum working temperature (160 °C). Especially, the gas sensor based on 2 at% CeO2-loaded In2O3 hollow spheres showed most improved properties: highly response (20.7–50 ppm) at 160 °C, which was about 3 times higher than that of pure In2O3 sensor (6.9); excellent response and recovery time of 1 s and 9 s; ultra-low detection of limit of 10 ppb; good repeatability and long-term stability. Finally, the enhanced gas sensing mechanism of CeO2-loaded In2O3 gas sensor towards H2 was also discussed.