Conductometric isopropanol gas sensor: Ce-doped In2O3 nanosheet-assembled hierarchical microstructure

Abstract

Pristine In2O3 nanosheets and Ce doped In2O3 hierarchical microstructures assembled by nanosheets were synthesized by a simple hydrothermal method with the following calcination by the aid of surfactants. The morphology and composition characterizations indicate that doping Ce enables to induce lattice distortion, beneficial for the sensing performance. Gas sensing tests indicate that doping Ce into In2O3 could significantly improve the sensing performance towards isopropanol. Among the various molar ratios of Ce doped samples, 4 at% Ce-In2O3 nanosheets exhibited the highest sensing response (93), which was 6 times higher than that of the pristine In2O3 towards 100 ppm isopropanol at the optimized working temperature of 220 °C. Furthermore, the Ce-In2O3 samples showed short response and recovery time, high selectivity, broad dynamic range and acceptable long-term stability. The enhanced mechanism was attributed to the changed lattice and band structures, better electron transfer ability, and increased charge carrier density.