Flexible H2 sensors fabricated by layer-by-layer self-assembly thin film of multi-walled carbon nanotubes and modified in situ with Pd nanoparticles

A novel flexible H2 gas sensor was fabricated by the layer-by-layer (LBL) self-assembly of thin film surface-oxidized multi-walled nanotubes (MWCNTs) on a polyester (PET) substrate. Then, a Pd-based complex was self-assembled in situ on the as-prepared MWCNTs thin film, which was reduced to form an MWCNT-Pd thin film. The thin films were characterized by scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The gas sensing properties, such as strength of the response, sensing linearity, reproducibility, response time, recovery time, cross-sensitivity effects and long-term stability were also investigated. The flexible H2 gas sensor exhibited a strong response that was comparable to or even greater than that of sensors that were fabricated on rigid substrate at room temperature.