Selectivity Modification of SnO2-Based Materials for Gas Sensor Arrays

An enhancement of selectivity of sensor materials, based on nanocrystalline SnO2 is reported. Selectivity toward target gases such as CO, NO2, NH3, H2S and acetone vapor, could be achieved by selection of catalytic cluster distributed over the surface of thick film material. Presented results allow us to propose application of obtained materials in "electronic nose" sensor systems

Materials Based on Modified SnO2 for Selective Gas Sensors

This paper presents an approach to improving the selectivity of gas sensors based on nanocrystalline tin dioxide. We demonstrate that chemical modification of the surface of SnO2 crystallites with catalytic metal oxide and gold clusters considerably enhances the selectivity of their sensing response to a variety of reducing gases at gas concentrations near the maximum permissible level. This approach can be used to produce "electronic nose" multisensor arrays

Catalytic impact of RuOx clusters to high ammonia sensitivity of tin dioxide

A comparative study of NH3-sensing performance of blank and modified nanocrystalline SnO2 was performed. Tin dioxide modified by ruthenium displayed the highest ammonia sensitivity with a maximum signal at 200°C. The modifier was shown by XPS and EPR to occur in a mixed valence state of oxidized ruthenium distributed between the surface and bulk of tin dioxide nanocrystals. RuOx clustering on SnO2 surface was detected by means of electron microscopy assisted EDX-mapping. The effect of RuOx on tin dioxide interaction with ammonia was studied by temperature-programmed NH3 desorption, simultaneous Kelvin probe and DC-resistance measurements, EPR spectroscopy and analyses of the gas-solid interaction products. The modifier was shown to promote the materials reactivity to NH3 due to the catalytic activity of RuOx. The interaction with ammonia resulted in dipoles formation on the oxide surface along with reducing the grains net surface charge, established from the electron affinity increase and resistance decrease during NH3 exposure. The RuOx-catalyzed gas-solid interaction was deduced to proceed deeper than in the case of non-modified SnO2 and to yield nitrogen oxides (e.g. NO2), as was suggested by the oxidative character of gaseous products of NH3 interaction with RuOx-modified tin dioxide at 200°C. © 2012 Elsevier B.V. All rights reserved

Chemically modified nanocrystalline SnO2-based materials for nitrogen-containing gases detection using gas sensor array

International audienceThis study is devoted to creation of metal oxide semiconductor (MOS) materials for gas sensor array for determination of nitrogen oxides and ammonia traces in sub-Threshold Limit Value (TLV) concentrations in air, and to elaboration of data processing algorithms for identification and quantification of single gases. The array contained semiconductor sensors made from originally synthesized gas sensitive materials - chemically modified nanocrystalline SnO2. The modifiers were preliminarily chosen on the basis of an analysis of the target gas properties and experimental data obtained in the field of heterogeneous catalysis on the Platinum Group metals and d-metal oxides. A novel algorithm for data analysis of a semiconductor gas sensor array working in a dynamic temperature mode is used. The ability of the suggested algorithm, called EDMN+ (from Euclidian Distance Matrix Normalization), to solve the task of gases identification, and the ability of PLS (Projection to Latent Structures) algorithm combined with cross-validation approach to solve the task of gases quantification using a limited amount of data patterns available, are demonstrated. (C) 2016 Elsevier B.V. All rights reserved

Chemically modified nanocrystalline SnO2-based materials for nitrogen-containing gases detection using gas sensor array

International audienceThis study is devoted to creation of metal oxide semiconductor (MOS) materials for gas sensor array for determination of nitrogen oxides and ammonia traces in sub-Threshold Limit Value (TLV) concentrations in air, and to elaboration of data processing algorithms for identification and quantification of single gases. The array contained semiconductor sensors made from originally synthesized gas sensitive materials - chemically modified nanocrystalline SnO2. The modifiers were preliminarily chosen on the basis of an analysis of the target gas properties and experimental data obtained in the field of heterogeneous catalysis on the Platinum Group metals and d-metal oxides. A novel algorithm for data analysis of a semiconductor gas sensor array working in a dynamic temperature mode is used. The ability of the suggested algorithm, called EDMN+ (from Euclidian Distance Matrix Normalization), to solve the task of gases identification, and the ability of PLS (Projection to Latent Structures) algorithm combined with cross-validation approach to solve the task of gases quantification using a limited amount of data patterns available, are demonstrated. (C) 2016 Elsevier B.V. All rights reserved