Layer-by-Layer Self-assembly of Co₃O₄ Nanorod-Decorated MoS₂ Nanosheet-Based Nanocomposite toward High-Performance Ammonia Detection

Abstract

This article is the first demonstration of a molybdenum disulfide (MoS 2 )/tricobalt tetraoxide (Co 3 O 4 ) nanocomposite film sensor toward NH 3 detection. The MoS 2 /Co 3 O 4 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 2 /Co 3 O 4 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 3 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 3 . Moreover, the MoS 2 /Co 3 O 4 nanocomposite film sensor exhibited significant enhancement in ammonia-sensing properties in comparison with the MoS 2 and Co 3 O 4 counterparts. The underlying sensing mechanisms of the MoS 2 /Co 3 O 4 nanocomposite toward ammonia were ascribed to the layered nanostructure, synergistic effect, and heterojunction created at the interface of n-type MoS 2 and p-type Co 3 O 4 . The synthesized MoS 2 /Co 3 O 4 nanocomposite proved to be an excellent candidate for constructing high-performance ammonia sensor for various applications.