In this paper, a quartz crystal microbalance (QCM)-based humidity sensor has been fabricated by colloidal tin oxide (SnO 2 ) nanowires. The SnO 2 nanowires were synthesized via a colloidal process that employing SnCl 4 ethanol solutions mixed with oleic acid (OA) and oleylamine (OLA). The spin-coating method was chosen to deposit the sensitive film at room temperature without high-temperature sintering. Furthermore, the Cu(NO 3 ) 2 methanol solution was used to remove the organic long chains coated on the surface of the colloidal SnO 2 nanowires and expose more adsorption sites. The characterizations of the material were studied by means of FTIR, XRD, and FE-SEM. The saturated salt solution method was used to investigate the humidity sensing performance (response, recovery, repeatability, etc.) of the QCM sensor in the range of 11%–97%. The results showed that the sample with 12 h synthesis has the best humidity response. This may be attributed to the larger specific surface area which makes the material provide more adsorption sites for water molecules, and more (110) planes formed which could absorb more water molecules proved by the Density Functional Theory (DFT) calculation.
Xiaolin Li,Xueming Li,Wenjing Yang,Xiaohua Chen,Wulin Li,Binbin Luo,Kuilong Wang
The PbO 2 nanospheres supported on SnO 2 nanowires at Ti substrate (PbO 2 nanospheres@SnO 2 NWs/Ti) electrode was successfully synthesized through hydrothermal method. The structure and morphology of the electrode were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical property was carried out by cyclic voltammogrametry (CV) and UV spectroscopy was used to monitor the changes during the electrochemical degradation process. The results showed that the as-prepared electrode exhibited a three-dimensional (3D) reticulated structure with a large surface area. The average diameter of a single PbO 2 nanosphere is about 300 nm. XRD distinctively identified that the PbO 2 nanospheres was mainly composed of tetragonal-shaped β-PbO 2 crystal. The CV results show that methyl orange (MO) can be oxidized on the electrode surface at the potential of +1.3 V vs. Ag/AgCl. As much as 92.7% of chemical oxygen demand (COD) was removed in 60 min at 25 °C and pH 5.0 with an applied current density of 15 mA/cm 2 . Proper degradation mechanism was also proposed.
危险品化学品经营许可证（带存储）