ジエトキシジメチルシランゾル溶液で浸漬処理したPd/SnO2センサーのガス検出特性
1998 年 106 巻 1234 号 p. 621-626
詳細
1998 年 106 巻 1234 号 p. 621-626
Dipping a sintered Pd/SnO2 sensor in a diethoxydimethylsilane sol solution, followed by calcination at 600°C, resulted in a considerable enhancement of gas sensitivity to H2 but a marked decrease to CH4 and C3H8. In good accordance with the variations in the gas-sensing properties, catalytic activity of the sensor material markedly decreased for CH4 and C3H8 oxidation but increased for H2 oxidation. TEM observation and EDX analysis revealed that the fine SnO2 particles were coated with thin SiO2 layers 2-3nm in thickness after dipping. Temperature programmed desorption chromatograms (TPD) of O2 and H2O were markedly influenced by the formation of thin SiO2 layers; that is, the amount of active O- or O2- species on SnO2 became considerably small, and the adsorbed species of H2O changed from surface hydroxyl groups to molecular species hydrogen-bonded on the surface oxygen ions. The mechansim of the H2 gas sensitivity enhancement was discussed from the viewpoint of the modifications in TPD characteristics.
