Crystalline structure controlled of In2O3 sensing platforms for sensitive H2S performance at low temperature

Regulation based on the crystalline structure modulations is capable of optimizing the band gap and chemisorbed oxygen components thus adjusting the gas sensing characteristics of sensing materials. Herein, In2O3 hierarchical-assembled microspheres with diverse crystalline structures were synthesized via a simple hydrothermal method combined with calcinating procedure under different temperatures. The gas sensor based on rhombohedral In2O3 (rh-In2O3) microspheres assembled by pine needle shaped nanorods annealed at 350 ℃ (350-In2O3) exhibited superior H2S sensing performances at relative low operating temperature of 100 ℃ with low detection limit (50 ppb) and optimized stability compared with cubic In2O3 (c-In2O3). Notably, H2S sensing characteristics of In2O3 samples with different crystalline structures certificated that crystal structures can dominate the H2S sensing reactions with different mechanisms. This work enlightened a novel prospect for designing rh-In2O3 based sensors and provides an innovative pathway for analyzing the feasible H2S sensing mechanisms.