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Herein, a novel hierarchical cactus-like WO 3 -SnO 2 nanocomposite was synthesized by a one-step hydrothermal route. It was a surprise to find that such nanostructure consisting of diminutive SnO 2 nanospheres decorated bulky WO 3 nanosphere exhibited a high gas response and fast response-recovery speed towards acetone, mainly attributed to their synergetic effect as well as the heterojunction at the interface between the bulky WO 3 nanosphere and diminutive SnO 2 nanosphere, resulting in adequate surface adsorption and efficient electron transport. [ABSTRACT FROM AUTHOR]

Abstract: Zinc tin oxide (ZnSnO3) materials, native and doped with Ti nanocomposites, were prepared by coprecipitation. In particular, we focus on the effect of Ti dopant on the ethanol sensing behavior of the ZnSnO3-based sensor. Results show that adding Ti ions evidently enhanced gas response of ZnSnO3. A gas adsorption model based on first principles was proposed to address the gas sensing mechanism. This study may open up an avenue for exploring other ABO3-type sensing materials. [Copyright &y& Elsevier]

Abstract: The microstructure of M-doped SnO2 (M=Cr3+, Cu2+ and Pd2+) prepared by the sol–gel method and their gas-sensing performance were investigated. In particular, we focus on the effects of metallic ions on the hydrogen sensing behavior of the SnO2-based sensor. It is found that hydrogen gas response of SnO2 can be enhanced evidently by adding Pd2+, while such effect from Cr3+ and Cu2+ exhibits somewhat slight. A theoretical study based on first principles calculation shows that SnO2–Pd (110) surface enable adsorb more H2 gas and receive larger electrons from adsorbed H2 molecule, thereby holding the potential for the improvement of gas response to hydrogen. [Copyright &y& Elsevier]

The long-term stability and the extension of the use time of gas sensors are one of the current concerns. Lowering the working temperature is one of the most effective methods to delay aging. In this paper, pure MoS2 and ZnO-MoS2 nanocomposites were successfully prepared by the hydrothermal method, and the morphological characteristics were featured by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Pure MoS2 and ZnO-MoS2 nanocomposites, as a comparison, were used to study the aging characteristic. The sensing properties of the fabricated gas sensors with an optimal molar ratio ZnO-MoS2 (Zn:Mo = 1:2) were recorded, and the results exhibit a high gas-sensing response and good repeatability to the acetylene detection. The working temperature was significantly lower than for pure MoS2. After aging for 40 days, all the gas-sensing response was relatively attenuated, and pure MoS2 exhibits a faster decay rate and lower gas-sensing response than nanocomposites. The better gas-sensing characteristic of nanocomposites after aging was possibly attributed to the active interaction between ZnO and MoS2. [ABSTRACT FROM AUTHOR]

The detection of decomposed components is one of the important means of condition monitoring of SF 6 gas insulation equipment, among which chemical sensing is a kind of method with great potential. In this paper, two-dimensional Ti 3 C 2 T x was used as the sensing material substrate, and WO 3 -Ti 3 C 2 T x with different WO 3 doping concentrations were prepared by a one-step hydrothermal method. These materials were used to detect SO 2 , one of the decomposition products of SF 6. The results show that WO 3 -Ti 3 C 2 T x has a response of 12.5 % to 50 ppm SO 2 at room temperature(20℃), and the response time and recovery time are 54 s and 47 s, respectively. At the same time, WO 3 -Ti 3 C 2 T x has an excellent selectivity and long-term stability. Therefore, it is believed that WO 3 -Ti 3 C 2 T x can be used as an excellent material for SO 2 gas sensing devices. • Three-dimensional porous WO 3 /Ti3C2Tx synthesized by one-step hydrothermal method. • The sensor exhibits high sensitivity, rapid response and recovery to low-concentration SO2 in room temperature(20℃). • Good linear response for a wide range of SO 2 gas concentrations. [ABSTRACT FROM AUTHOR]

The development of advanced materials for energy storage and gas sensing applications has gained significant attention in recent years. In this study, we synthesized and characterized PANI@MnO 2 @rGO ternary nanocomposites (NCs) to explore their potential in supercapacitors and gas sensing devices. The ternary NCs were synthesized through a multi-step process involving the hydrothermal synthesis of MnO 2 nanoparticles, preparation of PANI@rGO composites and the assembly to the ternary PANI@MnO 2 @rGO ternary NCs. The structural, morphological, and compositional characteristics of the materials were thoroughly analyzed using techniques such as XRD, FESEM, TEM, FTIR, and Raman spectroscopy. In the realm of gas sensing, the ternary NCs exhibited excellent performance as NH 3 gas sensors. The optimized operating temperature of 100 °C yielded a peak response of 15.56 towards 50 ppm NH 3. The nanocomposites demonstrated fast response and recovery times of 6 s and 10 s, respectively, and displayed remarkable selectivity for NH 3 gas over other tested gases. For supercapacitor applications, the electrochemical performance of the ternary NCs was evaluated using cyclic voltammetry and galvanostatic charge-discharge techniques. The composites exhibited pseudocapacitive behavior, with the capacitance reaching up to 185 F/g at 1 A/g and excellent capacitance retention of approximately 88.54% over 4000 charge-discharge cycles. The unique combination of rGO, PANI, and MnO 2 nanoparticles in these ternary NCs offer synergistic advantages, showcasing their potential to address challenges in energy storage and gas sensing technologies. Proposed NH 3 gas sensing mechanism for PANI@MnO 2 @rGO ternary nanocomposite based sensor. [Display omitted] • Synthesized PANI@MnO 2 @rGO NCs in multistep process. • Confirmed successful component integration with characterization techniques. • Explored NCs for supercapacitors and gas sensing applications. • Achieved gas response of 15.56 for 50 ppm NH 3 gas at optimized temperature. • Observed C sp of 185 F/g at 1 A/g with 88.54% retention over 4000 cycles. [ABSTRACT FROM AUTHOR]

The Ni-SnO 2 /g-C 3 N 4 composite exhibits unique hierarchical structure, which presents the gas response of 142.5 toward 10 ppm acetone at 125 °C. [Display omitted] • Hierarchical Ni-doped SnO 2 /g-C 3 N 4 nanocomposites are successfully synthesized. • The highly ordered Ni-doped SnO 2 nanosheets in situ grew onto g-C 3 N 4 lamina. • Ni-doped SnO 2 /g-C 3 N 4 presented the gas response of 142.5 toward 10 ppm acetone at 125 °C. • Introduction of g-C 3 N 4 formed g-C 3 N 4 -SnO 2 heterojunction and resulted in sharp resistance change. • Doping of Ni produced more oxygen vacancies for SnO 2. The development of metal oxides semiconductor-based gas sensors for the accuracy detection of acetone in human exhaled breath is highly desirable for diabetes diagnosis. Herein, we use calcining and hydrothermal method to grow highly ordered Ni-doped SnO 2 nanosheets onto g-C 3 N 4 lamina. The prepared Ni-SnO 2 /g-C 3 N 4 composite presents high gas response of 142.5 (Resistance ratio, defined as S = R air /R gas) toward 10 ppm acetone at the optimized operating temperature of 125 °C, under the environment temperature of 25 °C, 80 %RH. Moreover, the Ni-SnO 2 /g-C 3 N 4 based senor also maintains fast response–recovery time, good stability and extraordinary humidity resistance for detecting acetone, including the theoretical detection limit (LOD) as low as 1.38 ppb. The greatly improved gas sensing properties of the Ni-SnO 2 /g-C 3 N 4 composite can be due to the highly ordered hierarchical structure, Ni dopant and SnO 2 /g-C 3 N 4 heterojunctions. We believe this novel Ni-SnO 2 /g-C 3 N 4 nanocomposite promises to be a potential gas sensing material for diabetes diagnosis. [ABSTRACT FROM AUTHOR]

Abstract: The nanocomposite oxide (0.2TiO2–0.8SnO2) doped with Cd2+ powder have been prepared and characterized by XRD and their gas-sensing sensitivity were characterized using gas sensing measurement. Experimental results show that, bicomponent nano anatase TiO2 and rutile SnO2 particulate thick film doped with Cd2+ behaves with good sensitivity to formaldehyde gas of 200ppm in the air, and the optimum sensing temperature was reduced from 360°C to 320°C compared with the undoped Cd2+ thick film. The gas sensing thick films doped with Cd2+ also show good selectivity to formaldehyde among benzene, toluene, xylene and ammonia as disturbed gas and could be effectively used as an indoor formaldehyde sensor. [Copyright &y& Elsevier]