In situ formation of one-dimensional CoMoO4/MoO3 heterojunction as an effective trimethylamine gas sensor

In situ diffusion growth of CoMoO 4 nanoparticles on the surface of MoO 3 nanobelts was achieved through a facile method. The microstructures, morphologies, and chemical composition of the nanocomposites were investigated based on X-ray diffraction, field-emission electron scanning microscopy, transmission electron microscopy , energy dispersive spectroscopy, and X-ray photoelectron spectra. The characterization results confirmed CoMoO 4 nanoparticles uniformly distributed on the surface of the MoO 3 nanobelts. The trimethylamine sensing properties of pristine MoO 3 and CoMoO 4 /MoO 3 nanocomposites were investigated using a static system. The experimental results revealed that heterojunction structure of CoMoO 4 /MoO 3 nanocomposites displayed low working temperature and enhanced sensing performance. The response of CoMoO 4 /MoO 3 nanocomposites to 100   ppm trimethylamine was ∼104.8 at 220   °C, which was four times higher than that of pure MoO 3 at 280   °C. The reason for the enhanced sensing properties of CoMoO 4 /MoO 3 nanocomposites is attributed mainly to the formation of the p–n junction between the p-type CoMoO 4 nanoparticles and the n-type MoO 3 nanobelts.