SURFACE-RUTHENATED TIN OXIDE AS A NOVEL HYDROCARBON SENSOR

A surface-functionalized gas-sensing material capable of better sensit ivity and selectivity to hydrocarbons is demonstrated by grafting some Ru-O linkages on the surface of tin oxide. For example, the sensitivi ty towards 1000 ppm liquid petroleum gas (LPG) is found to be dramatic ally enhanced from 4 to 320 at 300 degrees C after this type of surfac e modification using ruthenium species. A systematic evaluation of the surface coverage, morphology, oxidation state and thermal stability u sing different techniques like EDAX, cyclic voltammetry, SEM, XPS and TGA indicates the crucial role of the optimum distribution of Ru speci es (0.27 wt.%) in dictating both selectivity and sensitivity. The resp onse time of the surface-modified sensor has also been found to be sig nificantly improved in comparison with pure tin oxide as a result of s urface functionalization. (C) 1998 Elsevier Science S.A.