Resumo

PICASSO, Gino et al. Sensors based on Ag-doped α-Fe2 O3 for the detection of hydrogen sulfide. Rev. Soc. Quím. Perú [online]. 2010, vol.76, n.3, pp.199-217. ISSN 1810-634X.

In this work, sensors based on undoped α-Fe₂O₃ and doped with Ag (metal loading ranging from 0,5 to 5% Wt) prepared by coprecipitation method for the detection of H₂S have been studied. Alumina has been used as material support of sensors and formvar (polyvinyl formal) as binder material. XRD patterns of all samples showed typical peaks of α-hematite. Mean particle size of nanoparticles evaluated by TEM was between 30 and 50 nm. BET isotherms showed that sensors presented mesoporous surface with mean surface area between 66 and 88 m2 /g. Sample tests of doped sensors with Ag showed higher sensibility than their undoped counterparts revealing catalytic effect of Ag on the surface reaction. In order to find optimal operating conditions (temperature and concentration), two groups of tests have been performed: first one were at constant propane concentration of 90 ppm in a temperature range from 159 °C to 388 °C and the second one were at constant temperatures of 159, 205 and 251 ºC in a concentration range of 30 to 90 ppm. Doped sensor with 0,5 % Ag presented higher sensibility at all operating temperatures and 90 ppm as hydrogen sulfide concentration and this behavior was attribuible to the presence of α-hematite morphology and higher thermal stability of sensor.

Palavras-chave : sensors; -Fe₂O₃; hydrogen sulfide.

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