Fabrication of platinum-loaded cobalt oxide/molybdenum disulfide nanocomposite toward methane gas sensing at low temperature

Abstract

A novel methane sensor based on platinum (Pt)-loaded cobalt oxide (Co3O4)/molybdenum disulfide (MoS2) nanocomposite was reported in this paper. The sensor was fabricated via layer-by-layer (LbL) self-assembly method for the first time, and was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), elemental mapping, transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing properties of the as-prepared Pt-Co3O4/MoS2 composite toward methane gas was investigated under various operating temperature, and the optimal working temperature of 170°C was determined. The Pt-Co3O4/MoS2 sensor exhibits superior gas sensing performance toward methane as compared to the Co3O4, Co3O4/MoS2 counterparts. The underlying gas sensing mechanism of the Pt-Co3O4/MoS2 sensor was systematically discussed, which demonstrates that the enhanced sensing performance of the sensor is attributed to the good synergistic effect of the ternary materials, including high availability of oxygen species, active catalytic effect, and special interactions at MoS2/Co3O4 heterojunction.