Highly selective low-temperature triethylamine sensor based on Ag/Cr2O3 mesoporous microspheres

Cr2O3 mesoporous microspheres were synthesized via an ethanol solvothermal process and Ag/Cr2O3 microspheres were prepared by a surfactant-modified method. The two products were characterized by XRD, EDX, XPS, TEM and HRTEM techniques. The diameter of Cr2O3 microspheres was 1-1.5 mu m, which were further constructed by the building blocks of nanoplates. The Ag/Cr2O3 microspheres kept the morphology and mesoporous structure of Cr2O3 microspheres and Ag nanoparticles were successfully deposited on the surface of Cr2O3 microspheres with the particle size of 7-25 nm. The gas sensing properties of the Cr2O3 and Ag/Cr2O3 microspheres to triethylamine (TEA) were measured at different working temperatures. The response of Cr2O3 microspheres to 50 ppm TEA was 15.2 at working temperature of 170 degrees C, while that of Ag/Cr2O3 increased to 52.9 at a lower temperature of 92 degrees C. The modification of Ag nanoparticles not only greatly lowered the optimum working temperature, enhanced the response of Cr2O3 microspheres to TEA gas, but also further improved the selectivity of the sensor to TEA. The significant improvement of Ag/Cr2O3 microspheres to TEA gas sensing property could be attributed to the modified Ag sensitization and catalytic effect, and mesoporous structure of Cr2O3 microspheres. (C) 2015 Elsevier B.V. All rights reserved.