Novel CO2 and CO gas sensor based on nanostructured Sm2O3 hollow microspheres

C.R. MICHEL, A.H. MARTÍNEZ-PRECIADO, R. PARRA, C.M. ALDAO, Y M.A. PONCE

SENSORS AND ACTUATORS B-CHEMICAL

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2014 vol. 202 p. 428 - 433

0925-4005

tSm2O3microspheres were prepared by the coprecipitation method, using samarium nitrate and formicacid. The size of the microspheres was in the range 1?6 m; however, extensive fragmentation wasobserved. An outstanding improvement of the microstructure was achieved by using an aqueous solu-tion of pectin. In this case, hollow and nanoporous microspheres, having little fragmentation, wereproduced. The evolution of the crystal structure with calcination temperature revealed the formationof single-phase cubic Sm2O3, at 600◦C. The effects of the calcination temperature and the concentrationof samarium nitrate, on the microstructure of Sm2O3, were investigated. For the gas sensing characteriza-tion, thick films were prepared with the as-prepared Sm2O3microspheres. The gas sensing performanceof Sm2O3sensor devices was enhanced when gold electrodes were used. Transient impedance measure-ments revealed a reproducible and reliable detection of carbon dioxide and carbon monoxide at 400◦C.The increase of the applied frequency produced stable and noiseless graphs. Furthermore, quantitativedetection of the test gases was revealed by impedance and polarization measurements