An amperometric hydrogen sensor based on Pt nanoparticles supported multi-wall carbon nanotubes

Abstract

An amperometric H-2 gas sensor was fabricated on microporous PTFE sheet using Pt NP-decorated on multiwalled carbon nanotubes (MWNTs) via wet chemical synthesis and vacuum filtration processes. The various material analysis methods such as SEM coupled with EDS, TEM, and XRD were employed in order to characterize microstructures, morphologies and elemental composition of the prepared Pt-MWNTs material. The electrode showed the nanoporous structures with intricate surface morphology as a consequence of Pt agglomerates bonded to MWNTs. The TEM and XRD results confirmed the small Pt nanoparticles (Pt NPs) sizes of 0.5-4.7 nm and the polycrystalline face-centered cubic (fcc) structures. The measured electrochemical surface area (ESA) of the Pt-MWNTs-modified glassy carbon electrode was 235.2 cm(2)/mg by using cyclic voltammetry (CV) which was 1.2 times higher than that of commercial 20 wt% Pt-C (E-Tek). Furthermore, amperometric gas sensing measurements were performed to evaluate the gas sensing properties of sensor. The Pt-MWNTs electrode shows high sensitivity of 0.269 mu A/ppm in H-2 detection, an excellent linear response, reproducibility and long term stability. Moreover, this electrode was also evaluated in terms of response and recovery times, high detective limit of cross-selectivity to interfering species such as CO, NH3. Therefore, the obtained results show good sensing performance of Pt-MWNTs electrode of H-2 detection.