Influence of Mono- and Bimetallic PtOx, PdOx, PtPdOx Clusters on CO Sensing by SnO? Based Gas Sensors.

ABSTRACT: To obtain a nanocrystalline SnO? matrix and mono- and bimetallic nanocomposites SnO?/Pd, SnO?/Pt, and SnO?/PtPd, a flame spray pyrolysis with subsequent impregnation was used. The materials were characterized using X-ray diffraction (XRD), a single-point BET method, transmission electron microscopy (TEM), and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) with energy dispersive X-ray (EDX) mapping. The electronic state of the metals in mono- and bimetallic clusters was determined using X-ray photoelectron spectroscopy (XPS). The active surface sites were investigated using the Fourier Transform infrared spectroscopy (FTIR) and thermo-programmed reduction with hydrogen (TPR-H?) methods. The sensor response of blank SnO? and nanocomposites had a carbon monoxide (CO) level of 6.7 ppm and was determined in the temperature range 60?300 °C in dry (Relative Humidity (RH) = 0%) and humid (RH = 20%) air. The sensor properties of the mono- and bimetallic nanocomposites were analyzed on the basis of information on the electronic state, the distribution of modifiers in SnO? matrix, and active surface centers. For SnO?/PtPd, the combined effect of the modifiers on the electrophysical properties of SnO? explained the inversion of sensor response from n- to p-types observed in dry conditions.

SUBMITTER: Kutukov P 

PROVIDER: S-EPMC6266303 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature