Room-temperature SO2 gas-sensing properties based on a metal-doped MoS2 nanoflower: an experimental and density functional theory investigation

Abstract

This paper demonstrates a sulfur dioxide (SO₂) gas sensor based on a transition-metal-doped molybdenum disulfide (MoS₂) nanocomposite synthesized via a facile single-step hydrothermal route. The Ni-doped, Fe-doped, Co-doped, and pristine MoS₂ film sensors were fabricated on a FR4 epoxy substrate with interdigital electrodes. The morphologies, microstructures, and compositions of as-prepared samples were fully examined using X-ray diffraction, energy dispersive spectroscopy, scanning electron microscopy, transmission electron microscope, and X-ray photoelectron spectroscopy. The gas-sensing properties of the four samples were systematically investigated at room temperature, and the Ni-doped MoS₂ film sensor was screened out as the optimal SO₂ sensor among the four sensors, exhibiting a relatively high response value, quick response/recovery time, and excellent stability toward SO₂ gas. Furthermore, in order to explain the experimental results, we used Materials Studio software to construct molecular models of adsorption systems and calculate the geometry, energy, and charge parameters via density functional theory (DFT) based on first principles. The sensing mechanism is also discussed in depth. Through a comprehensive research approach of combining experimentation with DFT simulation, this work suggests that an Ni-doped MoS₂ film sensor is able to detect SO₂ gas at room temperature.