The Heterostructures of CuO and SnOx for NO2 Detection

Controlling environmental pollution is a burning problem for all countries more than ever. Currently, due to the increasing industrialization, the number of days when the limits of air pollutants are over the threshold levels exceeds 80–85% of the year. Therefore, cheap and effective sensors are always welcome. One idea is to combine such solutions with cars and provide real-time information about the current pollution level. However, the environmental conditions are demanding, and thus the developed sensors need to be characterized by the high 3S parameters: sensitivity, stability and selectivity. In this paper, we present the results on the heterostructure of CuO/SnOx and SnOx/CuO as a possible approach for selective NO2 detection. The developed gas sensors exhibited lower operating temperature and high response in the wide range of NO2 and in a wide range of relative humidity changes. Material characterizations and impedance spectroscopy measurements were also conducted to analyze the chemical and electrical behavior.

PdO/PdO2 functionalized ZnO : Pd films for lower operating temperature H2 gas sensing

The improved hydrogen gas sensing performances of PdO-functionalized ZnO : Pd films compared to pristine ZnO : Pd are successfully reported in this work. The functionalized samples showed excellent sensing properties.

Capillary Filling of Ferrofluid in Homogeneous Hydrophilic PDMS Microchannels

The capillary filling speed of ferrofluid in hydrophilic polydimethylsiloxane (PDMS) microfluidic channels is investigated under various temperature and magnetic field conditions. Microchannels with a depth of 100 μm and widths ranging from 100 to 400 μm are fabricated using conventional photolithography techniques and an oxygen plasma bonding process. The capillary filling speed of the ferrofluid is measured experimentally and compared with that of DI water. It is found that the filling speed of the ferrofluid is significantly lower than that of DI water. Moreover, the filling speed reduces with a reducing channel width, an increasing ferrofluid concentration, a lower operating temperature, and an increased filling length. By contrast, the filling speed increases under the effects of an external magnetic field.

Mechanism of enhancing the formaldehyde sensing properties of Co3O4via Ag modification

Ag@Co3O4 hollow microspheres exhibit higher sensitivity to formaldehyde at a lower operating temperature, which is attributed to the catalytic effect of Ag nanoparticles and the Schottky barrier formed at the metal–semiconductor interface.

Synthesis and Harmful Gas Sensing Properties of Zinc Oxide Modified Multi-Walled Carbon Nanotubes Composites

Metal oxide semiconductors materials such as zinc oxide (ZnO) are often used in the fabrication of chemoresistive gas sensors, but ZnO materials require high operating temperatures to operate. In another side, carbon nanotubes (CNT) have many distinct properties and recently have been exploited as the next generation of sensors, including chemoresisitive type gas sensors. This study was aimed to investigate the performance of MWNT-ZnO composites as SO2 gas sensitive layer. By fabricate composites of MWNT and ZnO, have been obtained a sensitive layer that can be utilized for application as gas sensitive layer with relatively lower operating temperature. A sensitive layer of MWNT-ZnO based composites have been successfully fabricated on a alumina substrate and several characterization techniques has been performed, i.e. XRD, SEM and EDS to study the formed crystalline phase, the morphology of the nanostructures, and the elemental composition of synthesized composites. MWNT-ZnO sensitive layer was tested by exposure to SO2 gas at various operating temperatures and gas concentration. From the performance testing results, it could be found that the composite materials have a prospective as a gas sensor at lower operating temperature with short response time and good sensitivity.