Room-temperature, selective detection of benzene at trace levels using plasma-treated metal-decorated multiwalled carbon nanotubes

Hybrid materials consisting of oxygen plasma-treated multiwalled carbon nanotubes decorated with metal nanoparticles (e.g., Rh, Pd, Au or Ni) can be tailored for the recognition of benzene vapors with high sensitivity and selectivity. Metal nanoparticles donate or accept a significant amount of charge upon adsorption of a target molecule, so as to affect electron transport in the nanotube. The plasma treatment enables the cleaning, activation, functionalization and metal decoration of carbon nanotubes in a single step, which offers enormous flexibility for tuning the interfacial properties of the resulting hybrid materials. When combined in a microsensor array operating at room temperature, the use of benzene-sensitive and benzene-insensitive metal-decorated multiwalled carbon nanotubes can provide selective detection of benzene at trace levels with a detection limit below 50 ppb.