Layer-by-Layer Self-assembly of Co 3 O 4 Nanorod-Decorated MoS 2 Nanosheet-Based Nanocomposite toward High-Performance Ammonia Detection

This article is the first demonstration of a molybdenum disulfide (MoS )/tricobalt tetraoxide (Co O ) nanocomposite film sensor toward NH detection. The MoS /Co O film sensor was fabricated on a substrate with interdigital electrodes via layer-by-layer self-assembly route. The surface morphology, nanostructure, and elemental composition of the MoS /Co O samples were examined by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy-dispersive spectrometry, and X-ray photoelectron spectroscopy. The characterization results confirmed its successful preparation and rationality. The NH sensing properties of the sensor for ultra-low-concentration detection were investigated at room temperature. The experimental results revealed that high sensitivity, good repeatability, stability, and selectivity and fast response/recovery characteristics were achieved by the sensor toward NH . Moreover, the MoS /Co O nanocomposite film sensor exhibited significant enhancement in ammonia-sensing properties in comparison with the MoS and Co O counterparts. The underlying sensing mechanisms of the MoS /Co O nanocomposite toward ammonia were ascribed to the layered nanostructure, synergistic effect, and heterojunction created at the interface of n-type MoS and p-type Co O . The synthesized MoS /Co O nanocomposite proved to be an excellent candidate for constructing high-performance ammonia sensor for various applications.