Highly sensitive NO2 detection on ppb level by devices based on Pd-loaded In2O3 hierarchical microstructures

The special flower-like Pd-loaded indium oxide (In2O3) hierarchical microstructures with different Pd contents were successfully synthesized by a hydrothermal method, showing the features dimension of 5-7 mu m diameter and 30 nm thick nanosheets. Developed NO2 sensors based on 1 mol% Pd-loaded In2O3 hierarchical microstructures demonstrated excellent NO2 detection at the ppb levels at lower operating temperature of 110 degrees C. These sensors also exhibited high response, fast response (180s) and recovery (90 s) time and great reliability as well as simplicity in fabrication. Furthermore, selective detection of NO2 can be readily achieved with sensors attached with 1 mol% Pd-loaded In2O3 even with other common chemicals such as ethanol, CO, CH4 and H-2 around. The electron depletion theory was used to explain the enhanced gas sensing mechanism. (C) 2017 Elsevier B.V. All rights reserved.