Catalytic NO_x removal by single-wall carbon nanotube-supported Rh nanoparticles

Single-wall carbon nanotubes functionalized with polyethylene glycol and doped with Rh nanoparticles were prepared and tested as catalyst for NO_x reduction. Gravimetric adsorption studies were employed to elucidate the mechanism of NO adsorption on the active surface sites and to determine the onset of the desorption of oxygen. These studies provided information about the reaction kinetics and the lifetime of the catalyst, as well as the NO scission onset temperature and abatement rate, thus making possible to predict the conversion and define the optimum reaction conditions for efficient NO removal. Catalytic experiments were performed under different operating conditions and feed compositions, such as under rich operation, in presence of oxygen, and in presence of reducing CO and hydrocarbons. The developed nanostructured catalyst exhibits enhanced activity at lower temperatures in comparison to that reported for other Rh-based catalytic systems, while data about feed composition effects and carbon support depletion provided operating conditions that suppress N₂O formation and extent the catalyst lifetime.