Facile one-step synthesis of TiO2 microrods surface modified with Cr2O3 nanoparticles for acetone sensor applications

The paper demonstrated cost-effective one-step hydrothermal process to synthesize TiO 2 microrods modified with Cr 2 O 3 nanoparticles. The crystal structure, microstructure and chemical composition of the obtained materials were characterized by XRD, SEM, TEM and EDS analysis. Subsequently, for gas sensor tests the sensors were fabricated onto a ceramic tube having a designed pair of Au electrodes with four Pt wires. The results indicate that the sensors based on the optimal content of Cr 2 O 3 nanoparticles modified TiO 2 microrods possess excellent gas-sensing performance to acetone. Specifically, the sensor based on optimal 3% Cr 2 O 3 modified TiO 2 microrods exhibited high response (15), fast response/recovery time (5/28 s), outstanding selectivity (against 100 ppm ethanol, methanol and formaldehyde) and good stability (1–40 days) towards 100 ppm acetone at 300 °C. Relying on the analysis, we infer that performance can be controlled by varying the Cr 2 O 3 contents. A plausible sensing mechanism is also discussed to explain the reasons for the enhanced acetone sensing with Cr 2 O 3 –TiO 2 heterostructures.