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

In situ diffusion growth of CoMoO4 nanoparticles on the surface of MoO3 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 CoMoO4 nanoparticles uniformly distributed on the surface of the MoO3 nanobelts. The trimethylamine sensing properties of pristine MoO3 and CoMoO4/MoO3 nanocomposites were investigated using a static system. The experimental results revealed that heterojunction structure of CoMoO4/MoO3 nanocomposites displayed low working temperature and enhanced sensing performance. The response of CoMoO4/MoO3 nanocomposites to 100 ppm trimethylamine was ∼104.8 at 220 °C, which was four times higher than that of pure MoO3 at 280 °C. The reason for the enhanced sensing properties of CoMoO4/MoO3 nanocomposites is attributed mainly to the formation of the p-n junction between the p-type CoMoO4 nanoparticles and the n-type MoO3 nanobelts.