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Highlights • Porous 3D SnO 2 are synthesized via a facile hydrothermal method. • Compared with some previous studies, 3D SnO 2 has improved gas sensitivity to CH 4. • The CH 4 sensor has good linear relationship in a wider range of gas concentration. Abstract Porous three-dimensional (3D) hierarchical flower-like SnO 2 nanomaterials were successfully synthesized via facile hydrothermal method combined with subsequent annealing process. Characterization analysis shows that the porous 3D SnO 2 consists of a number of thin nanosheets with pores. Gas sensing properties indicate that the porous 3D SnO 2 sensor has lower initial response temperature and optimal working temperature, better linearity in a certain range of gas concentration, better stability and selectivity to methane. Implies that porous 3D SnO 2 nanomaterials will be promising candidates for methane sensors. [ABSTRACT FROM AUTHOR]

Ultrafine nanoparticles conglomerated α-Fe 2 O 3 nanospheres were synthesized by laser irradiation of Fe(CO) 5 in acetone. As-prepared products were characterized by transmission electron microscopy, scanning electron microscopy and X-ray diffraction analysis techniques. Such obtained α-Fe 2 O 3 nanospheres were used as gas-sensing materials, which exhibit good selectivity, fast response and excellent cycle performance to ethanol molecules. [ABSTRACT FROM AUTHOR]

Curly porous NiO nanosheets were successfully fabricated by a simple hydrothermal approach. Changing the amount of ammonia, we obtained NiO nanosheets with different morphologies. Thus it could be seen the important role of ammonia in synthesizing curly porous NiO nanosheets. The structure, morphologies and gas-sensing properties of these samples were studied. Among these samples, the curly porous NiO nanosheets sensor exhibits significant improvement on ethanol gas sensing properties. [ABSTRACT FROM AUTHOR]

• It is the first time that Co-InN is used as the adsorbent to remove the decomposition components of SF 6 -N 2. • Co-InN shows good adsorption properties to NO 2 , SOF 4 , SOF 2 , SO 2 F 2 by chemisorption. • The theoretical calculation results are important to guide the development of resistive gas sensor based on the Co-InN. This paper presents a detection method of partial discharge decomposition components of SF 6 -N 2 mixture by Co-doped InN. The severity of partial discharge in gas insulated switchgear (GIS) can be judged by the gas components when SF 6 -N 2 decomposes. Exploring sensors with excellent gas-sensing detection capabilities can provide method to partial discharge decomposition component detection and fault diagnosis of GIS. Undoped InN is a wide bandgap semiconductor with good sensing properties. In this paper, the adsorption of SF 6 -N 2 decomposition components on Co-doped InN monolayer, as well as the adsorption mechanism and gas sensitivity characteristics were investigated by density functional theory (DFT), including adsorption energy, charge transfer, the density of state theory and molecular orbital theory. Our calculations found that Co-doped InN has the optimal structure at the T N site and has good adsorption performance for NO 2 , SOF 4 , SOF 2 , and SO 2 F 2 gas molecule. All adsorption reactions belong to chemisorption. These results could direct the development of gas sensor based on the Co-doped InN monolayer, and provides methods to online monitoring of GIS discharge failures. [ABSTRACT FROM AUTHOR]

Abstract: Tetrapod-shaped ZnO nanopowders were prepared by the method of vapor-phase oxidation from metallic zinc as raw materials. The gas-sensing properties of thick film based on tetrapod-shaped ZnO nanopowders to volatile organic compounds (VOCs), benzene, toluene, xylene, alcohol and acetone were measured, and compared with that of commercial ZnO powders with granular shape. The results showed that tetrapod-shaped ZnO had the better gas-sensing properties: the maximum sensitivity temperature was reduced, the gas sensitivity was improved and the time of response–recovery was shortened. The differences in gas-sensing properties between the thick films were discussed in according to the morphological characteristics, size and agglomeration of raw powder as well as microstructure of sintered thick films. [Copyright &y& Elsevier]

This paper reports that nano-La0.7Pb0.3FeO3 powders can be used as a new type of gas-sensing material for detecting ethanol gas. La0.7Pb0.3FeO3 powders were prepared by the citric method. The powders were characterized by X-ray diffraction (XRD), and XRD pattern showed that La0.7Pb0.3FeO3 was still perovskite phase with orthorhombic structure and its crystallite size is about 17 nm. The conductivity and gas sensitivity of La0.7Pb0.3FeO3-based sensor were investigated. The sensor exhibited high sensitivity and good selectivity towards ethanol gas. [Copyright &y& Elsevier]

• TiO 2 //SnO 2 Janus nanofibers are synthesized by a parallel electrospinning method. • TiO 2 //SnO 2 Janus nanofibers exhibits good gas sensing properties to ethanol. • SnO 2 /TiO 2 heterojunction and the Janus structure improved the sensing properties. Achieving a novel nanostructure is the key to improve the gas sensing properties of metal oxide semiconductor (MOS). Herein, [PVP/Ti(SO 4) 2 ]//[PVP/SnCl 4 ] composite Janus nanofibers (NFs) are synthesized by a parallel electrospinning method and TiO 2 //SnO 2 Janus NFs are obtained by calcining the composite. To investigate potential gas sensing application of the TiO 2 //SnO 2 Janus NFs, commercial gas sensor based on the TiO 2 //SnO 2 Janus NFs was fabricated, ethanol was selected as the target gas and the gas sensing properties were measured. The results indicated that the TiO 2 //SnO 2 Janus NFs displayed a quick response-recovery and good selectivity to ethanol. Additionally, a possible mechanism of the improved sensing abilities is also illustrated, which can provide guidance for the development of gas-sensitive NFs with Janus structure. [ABSTRACT FROM AUTHOR]