Ultrathin Leaf-Shaped CuO Nanosheets Based Sensor Device for Enhanced Hydrogen Sulfide Gas Sensing Application

Abstract

Herein, a simple, economical and low temperature synthesis of leaf-shaped CuO nanosheets is reported. As-synthesized CuO was examined through different techniques including field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray diffraction (XRD), fourier transform infrared spectroscopic (FTIR) and Raman spectroscopy to ascertain the purity, crystal phase, morphology, vibrational, optical and diffraction features. FESEM and TEM images revealed a thin leaf-like morphology for CuO nanosheets. An interplanar distance of ~0.25 nm corresponding to the (110) diffraction plane of the monoclinic phase of the CuO was revealed from the HRTEM images XRD analysis indicated a monoclinic tenorite crystalline phase of the synthesized CuO nanosheets. The average crystallite size for leaf-shaped CuO nanosheets was found to be 14.28 nm. Furthermore, a chemo-resistive-type gas sensor based on leaf-shaped CuO nanosheets was fabricated to effectively and selectively detect H2S gas. The fabricated sensor showed maximum gas response at an optimized temperature of 300 °C towards 200 ppm H2S gas. The corresponding response and recovery times were 97 s and 100 s, respectively. The leaf-shaped CuO nanosheets-based gas sensor also exhibited excellent selectivity towards H2S gas as compared to other analyte gases including NH3, CH3OH, CH3CH2OH, CO and H2. Finally, we have proposed a gas sensing mechanism based upon the formation of chemo-resistive CuO nanosheets.

Catalyzing Viologen Electrochromic Reaction with CuOx Nanoparticles

“…[41,42] HRTEM image of CuO x nanoparticles in Figure 2b demonstrated interplanar spacing of 0.25 nm that corresponds to (−111) planes of monoclinic CuO. [43,44] Besides, the interplanar distance of (−111) can be calculated by the Bragg's Law:…”

“…[ 41,42 ] HRTEM image of CuO x nanoparticles in Figure 2b demonstrated interplanar spacing of 0.25 nm that corresponds to (−111) planes of monoclinic CuO. [ 43,44 ] Besides, the interplanar distance of (−111) can be calculated by the Bragg's Law: $$$$\begin{equation}{{\mathrm{D}}}_{\left( { - 111} \right)} = \frac{{{\lambda}}}{{2{\mathrm{sin\theta }}_{\left( { - 111} \right)}}}\ \end{equation}$$$$where λ is wavelength of the X‐ray used ( λ = 0.154 nm) and θ is the Bragg angle of the (−111) diffraction peak (2 θ = 35.5°). Consequently, the calculated interplanar distance of (−111) is 0.265 nm, which is basically consistent with the HRTEM result.…”

p-CuO/n-ZnO Heterojunction Structure for the Selective Detection of Hydrogen Sulphide and Sulphur Dioxide Gases: A Theoretical Approach

“…Furthermore, the sensor action was prominently dependent on the recovery time ( τ ). Equation (4) shows that the τ increased as the released adsorption energy (Eads) increased (more negative). Table 2 shows that the Eads values for SO2/Cu2Zn10O12 and H2S/Cu2Zn10O12 were −2.640 and −1.576 eV, respectively.…”

“…Environmental pollution has recently reached an alarming level as a result of fast industrialization, which has resulted in an increase in the number of poisonous and dangerous gases and chemicals in the atmosphere [1][2][3][4]. Because of their colorless and odorless nature, most gases are breathed by humans without their knowledge, causing serious health problems and even death [5][6][7][8].…”

“…Metal oxide semiconductor (MOS)-based resistive sensors have recently attracted a lot of interest because of their ease of manufacture and inexpensive cost, as well as their quick, programmable, sensitive, and selective response [27][28][29][30][31][32][33]. The performance of MOSbased sensors can be improved by using semiconductor metal oxide nanomaterials as sensing material because the nanomaterials have a higher specific surface area, which increases the interaction between the sensing material and the target gas and, thus, improves the sensing response [1,2,4,5]. Metal oxide nanomaterials such as zinc oxide (ZnO), copper oxide (CuO), tin oxide (SnO2), tungsten oxide (WO3), nickel oxide (NiO), cobalt oxide (Co3O4), iron oxide (Fe2O3), titanium oxide (TiO2), indium oxide (In2O3), vanadium oxide (V2O5), molybdenum oxide (MoO3), and others are used to fabricate efficient MOS sensors [28][29][30][31][32][33][34][35][36][37].…”