Enhancement in ethanol sensing response by surface activation of ZnO with SnO2

A surface functionalized gas sensing material convincingly giving enhanced response to ethanol is demonstrated by SnO2 activated ZnO. Zinc oxide was synthesized by a chemical route, deposited on an alumina substrate and activated by tin dioxide obtained by on-site oxidation of tin chloride. The XRD study of samples confirmed wurtzite hexagonal structure of zinc oxide and FESEM investigation revealed that surface of activated ZnO microrods was covered by nanoparticles of tin dioxide. Sensing response of sensing elements activated with different concentrations of tin chloride solution has been investigated. It was found that response to ethanol vapor significantly enhanced (eight times) by surface activation with tin dioxide, which optimized at a concentration of 3 wt.%.

Sensing response versus time for pure and SnO2 activated ZnO gas sensor to 250 ppm ethanol at 400 °C.Figure optionsDownload as PowerPoint slideHighlights
► Surface modification of ZnO thick film with SnO2.
► Surface of activated ZnO microrods covered by nanoparticles of tin dioxide.
► Significant enhancement (8 times) in sensing response by surface activation.