Hybrid SnO2/TiO2 Nanocomposites for Selective Detection of Ultra-Low Hydrogen Sulfide Concentrations in Complex Backgrounds

Abstract

In this paper, we present a chemiresistive metal oxide (MOX) sensor for detection of hydrogen sulfide. Compared to the previous reports, the overall sensor performance was improved in multiple characteristics, including: sensitivity, selectivity, stability, activation time, response time, recovery time, and activation temperature. The superior sensor performance was attributed to the utilization of hybrid SnO2/TiO2 oxides as interactive catalytic layers deposited using a magnetron radio frequency (RF) sputtering technique. The unique advantage of the RF sputtering for sensor fabrication is the ability to create ultra-thin films with precise control of geometry, morphology and chemical composition of the product of synthesis. Chemiresistive films down to several nanometers can be fabricated as sensing elements. The RF sputtering technique was found to be very robust for bilayer and multilayer oxide structure fabrication. The geometry, morphology, chemical composition and electronic structure of interactive layers were evaluated in relation to their gas sensing performance, using scanning electron microscopy (SEM), X-ray diffraction technique (XRD), atomic force microscopy (AFM), Energy Dispersive X-ray Spectroscopy (EDAX), UV visible spectroscopy, and Kelvin probe measurements. A sensor based on multilayer SnO2/TiO2 catalytic layer with 10% vol. content of TiO2 demonstrated the best gas sensing performance in all characteristics. Based on the pattern relating material’s characteristics to gas sensing performance, the optimization strategy for hydrogen sulfide sensor fabrication was suggested.

Multisensory Gas Chromatography for Field Analysis of Complex Gaseous Mixtures

“…The integrated multi-sensor platform (2.5 mm × 2.5 mm × 0.3 mm) was designed to control the operation of four sensor elements at high temperatures, providing synchronized multisensory analysis of gas samples. The integrated multisensory platform is owned by VAON LLC [21][22][23]. This design provides high detector stability over a long period of time at elevated temperatures in the range between 200 and 600 °C.…”

“…The sensor S1 was left unmodified. The surface of sensor S2 was The integrated multisensory platform is owned by VAON LLC [21][22][23]. This design provides high detector stability over a long period of time at elevated temperatures in the range between 200 and 600 • C. The multisensory platform consists of four pairs of platinum electrodes for four identical sensing elements and a platinum cross-shaped heater located on the suspended membrane (1.5 mm × 1.5 mm × 0.05 mm) at the center of the platform (Figure 1a,b).…”

“…The thicknesses of all the layers were monitored during the deposition process by using a quartz crystal sensor (Inficon, Bad Ragaz, Switzerland, Gold, 6Mhz) and verified by a surface profilometer (Alpha Step 500, KLA Tencor, Milpitas, CA, USA). More information on the novel integrated detector is found in the works [21][22][23]. More information on the novel integrated detector is found in the works [21][22][23].…”

“…More information on the novel integrated detector is found in the works [21][22][23]. More information on the novel integrated detector is found in the works [21][22][23]. The table-top MGC setup and its schematic diagram are shown in the Figures 3 and 4, respectively.…”

Metabolic Syndrome—An Emerging Constellation of Risk Factors: Electrochemical Detection Strategies

“…Employment of hybrid nano-interface materials for multiple-analyte detection has been proved to improve sensor performance as well as reduce the response time [72,73]. The techniques like CV (cyclic voltammetry), Amp (amperometry), CA (Chronoamperometry), EIS (Electrochemical impedance spectroscopy) and DPV (differential pulse voltammetry) are among electrochemical methods that provide different information on the interactions between the analyte and sensing element at the electrode-electrolyte interface.…”