Ratio Of SnO2 Research Articles

Sensitivity enhancement for H 2 gas detection using a SnO 2–Ag 2O–PdO x nanocrystalline system

Thick film H 2 sensors were fabricated using SnO 2 loaded with Ag 2O and PdO x . The composition that gave highest sensitivity for H 2 was in the wt.% ratio of SnO 2:Ag 2O:PdO x as 93:5:2. The nano-crystalline powders of SnO 2–Ag 2O–PdO x composites synthesized by sol–gel method were screen printed on alumina substrates. Fabricated sensors were tested against gases like H 2, CH 4, C 3H 8, C 2H 5OH and SO 2. The composite material was found sensitive against H 2 at the working temperature 125 °C, with minor interference of other gases. H 2 gas as low as 100 ppm can be detected by the present fabricated sensors. It was found that the sensors based on SnO 2–Ag 2O–PdO x nanocrystalline system exhibited high performance, high selectivity and very short response time to H 2 at ppm level. These characteristics make the sensor to be a promising candidate for detecting low concentrations of H 2.

On the correlation between morphology and gas sensing properties of RGTO SnO 2 thin films

In this paper, we present the results of studies on optimalisation of morphology of the SnO 2 thin films grown by RGTO technique for application as gas sensor structures. The Sn thin films were grown on Si(111) wafer and Al 2O 3 ceramic plate heated in the range 235–295 °C and subsequently oxidized in dry oxygen atmosphere at high temperature, up to 700 °C. Our studies confirmed that the highest surface coverage of Sn droplets can be reached for the substrate temperature of about 265 °C leading to the highest surface-to-volume ratio of SnO 2 thin films. It was in a good correlation to the optimal gas sensor response and sensor sensitivity of RGTO SnO 2 thin films to nitrogen dioxide NO 2.

Nonlinear Electrical Behaviour of CompositeSnO2–Zn2SnO4 System

We have found a new composite SnO2–Zn2SnO4varistor material and the effect of different content ratios ofSnO2 to Zn2SnO4 on this system is investigated.The lowest breakdown voltage (EB = 6.4 V/mm) and the highestrelative dielectric constant (εr = 1.54×104) withhigher nonlinear coefficient (α = 4.5) is obtained when the ratioof SnO2 to ZnO equals 100/35. The disappear of theZn2SnO4 peak in x-ray diffraction (XRD) spectra of theSnO2+2.5 mol%ZnO sample and the electric insulation behaviour ofthe samples with 2.5 mol% ZnO and 200 mol% ZnO indicate that2.5 mol% ZnO can be dissolved into SnO2 lattices and some reactioncontributing to nonlinear electrical behaviour should occur betweenSnO2 and Zn2SnO4. The role of oxygen on the grainboundary is confirmed by the degradation of nonlinear electricalproperties and the increase of relative dielectric constant of thesamples annealed in nitrogen-rich atmosphere.

Sensitivity enhancement for CO gas detection using a SnO 2–CeO 2–PdO x system

Thick film CO sensors were fabricated using SnO 2 loaded with CeO 2 and PdO x . The composition that gave highest sensitivity for CO was in the wt.% ratio of SnO 2:CeO 2:PdO x as 94:5:1. The nano-crystalline powders of SnO 2–CeO 2–PdO x composites synthesized by sol–gel method were screen-printed on alumina substrates. The fabricated sensors were also tested against other gases like H 2, CH 4, C 3H 8, C 2H 5OH, NO x and SO 2. The composite material was found sensitive against CO in the working temperature range between 120 and 180 °C, with minor interference of other gases. The CO gas as low as 40 ppm can be detected by the present fabricated sensors.