Abstract
ZnO quantum dots sensitized SnO2 porous nanowires were fabricated and designed for UV excitation gas sensor. The ZnO/SnO2 composite (SZQ1%) with the molar proportion of 1:100 exhibits excellent sensing properties to NO2 gas under UV irradiation at 40oC. The humidity stability of SZQ1% was also measured and discussed by DC reversed circuit and complex impedance curves. The gas sensing mechanism is well discussed and illustrated to the ZnO quantum dots sensitized and the increased photo-generated carriers under UV irradiation.
Ultrathin polycrystalline bismuth (2D-Bi) nanosheets is developed as the multifunctional electrocatalyst for polysulfide conversion. And an in-depth understanding of the distinctive electrocatalysis mechanism of 2D-Bi is revealed by steady-state and dynamic electrochemical methods.
We have fabricated a low-cost and flexible NH3 gas sensor using thermal ink-jet printing. The poly (3,4-ethylene dioxythiophene) doped with polystyrene sulfonated acid (PEDOT/PSS) with thickness of ~ 2 μm was used as a sensing film. The interdigitated electrode using patterned aluminum plate was attached over the sensing film. Atomic force microscopy results show the high homogeneous film and only small roughness is presented on the sensing film. This sensor exhibits high selectivity and sensitivity to NH3 at room temperature. The sensor response works linearly with gas concentrations between 100-1000 ppm. The modulation of conducting polymer/metal electrode interface plays a role in the sensing mechanism of NH3. Changes in the position of interdigitated electrodes can change the dominant sensing mechanism of typical polymer gas sensor.
In this paper, the gas sensors using WO3 as sensitive electrode, Pt mixed potential as the reference electrode was researched. The structures and preparation methods of the sensors were introduced. Besides, the sensitive materials, the electrode surface and the section morphologies were characterized by means of SEM and EDS. Furthermore, the sensing properties of the as-fabricated sensors were examined under different NOX concentrations and temperatures (500°C, 550°C and 600°C). The results revealed that the response signal become smaller with the temperature increasing, and stronger with the increasing of the NO2 concentration.
Improvement of NO2 sensing characteristic for mixed potential type gas sensor based on YSZ and Rh/Co3V2O8 sensing electrode