Hexagonal-shaped nanoplates (HNPs) of MoS2 on vertically aligned carbon nanotubes (CNTs) over a patterned area (a circular area of 1 cm2 diameter) are produced by chemical vapor deposition technique. With an optimized initial Mo film thickness, a uniform coverage of MoS2 HNPs with a thickness around 20 nm is achieved. The results confirm that the CNT template plays an important role in the MoS2 HNPs growth. Each MoS2 HNP consists of abundant exposed edges, interesting for sensing and catalysis applications. High crystallinity and quality of the as-produced material are revealed by X-ray photoelectron and Raman spectroscopies. Furthermore, NO2 gas-sensing studies show better sensitivity and recovery for MoS2/CNT samples as compared to pristine CNTs. The detection of NO2 gas in a few tens of parts per million to a few hundreds of parts per billion range, at room temperature, is achieved. Density-functional theory calculation indicates that the exposed edges of MoS2 play a significant role in the NO2 sensing as compared to horizontally aligned MoS2 layers. The present report can promote the research toward the fabrication of efficient and reliable MoS2-based hybrid materials for toxic gas-sensing applications for air quality monitoring in various environments.
Patterned 3D hierarchical MoS2 hexagonal nanoplates with exposed edges are synthesized on vertically aligned carbon nanotubes by a simple chemical vapor deposition technique. The as-grown hybrid heterostructure with only top contacts, shows excellent NO2 gas-sensing properties over a few ppb to a few hundreds of ppm range.
- DFT calculations
- gas sensor