Somacescu Simona, Stanoiu Adelina, Dinu Ion Viorel, Calderon-Moreno Jose Maria, Florea Ovidiu G, Florea Mihaela, Osiceanu Petre, Simion Cristian E
"Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest, Romania.
National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania.
Materials (Basel). 2021 Jan 19;14(2):465. doi: 10.3390/ma14020465.
The paper presents the possibility of detecting low HS concentrations using CuWO. The applicative challenge was to obtain sensitivity, selectivity, short response time, and full recovery at a low operating temperature under in-field atmosphere, which means variable relative humidity (%RH). Three different chemical synthesis routes were used for obtaining the samples labeled as: CuW1, CuW2, and CuW3. The materials have been fully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). While CuWO is the common main phase with triclinic symmetry, different native layers of CuO and Cu(OH) have been identified on top of the surfaces. The differences induced into their structural, morphological, and surface chemistry revealed different degrees of surface hydroxylation. Knowing the poisonous effect of HS, the sensing properties evaluation allowed the CuW2 selection based on its specific surface recovery upon gas exposure. Simultaneous electrical resistance and work function measurements confirmed the weak influence of moisture over the sensing properties of CuW2, due to the pronounced Cu(OH) native surface layer, as shown by XPS investigations. Moreover, the experimental results obtained at 150 °C highlight the linear sensor signal for CuW2 in the range of 1 to 10 ppm HS concentrations and a pronounced selectivity towards CO, CH, NH, SO, and NO. Therefore, the applicative potential deserves to be noted. The study has been completed by a theoretical approach aiming to link the experimental findings with the CuW2 intrinsic properties.
本文介绍了使用CuWO检测低浓度HS的可能性。应用方面的挑战是在现场大气条件下（即相对湿度可变的情况下），在较低的工作温度下获得灵敏度、选择性、短响应时间和完全恢复能力。采用了三种不同的化学合成路线来制备标记为CuW1、CuW2和CuW3的样品。通过X射线衍射（XRD）、扫描电子显微镜（SEM）、拉曼光谱和X射线光电子能谱（XPS）对材料进行了全面表征。虽然CuWO是具有三斜对称性的常见主相，但在其表面顶部已鉴定出不同的CuO和Cu(OH)原生层。它们在结构、形态和表面化学方面的差异揭示了不同程度的表面羟基化。鉴于HS的毒害作用，传感性能评估基于CuW2在气体暴露后的特定表面恢复情况，从而选择了CuW2。同时进行的电阻和功函数测量证实，由于XPS研究表明存在明显的Cu(OH)原生表面层，水分对CuW2传感性能的影响较弱。此外，在150°C下获得的实验结果突出了CuW2在1至10 ppm HS浓度范围内的线性传感器信号以及对CO、CH、NH、SO和NO的显著选择性。因此，其应用潜力值得关注。该研究还通过一种理论方法得以完善目标是将实验结果与CuW2的固有特性联系起来。
