Evaluation of carbon nanotubes produced from toluene steam reforming as catalyst support for selective catalytic reduction of NO_x

There is current interest in developing low cost, effective catalysts for the low temperature selective catalytic reduction (SCR) of nitrogen oxides (NO_x). In this work, we have applied carbon nanotubes (CNTs), produced as a by-product of hydrogen production from the steam reforming of toluene (as a representative hydrocarbon), as a catalyst support for a V₂O₅-WO₃ catalyst for SCR of NO_x. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showed well dispersed metals on the surface of the CNTs. The V2O5-WO3/CNT catalyst has exhibited NO_x reduction efficiency higher than 95% at reaction temperatures between 340 and 400 °C. However, there was a low NO_x reduction at SCR reaction temperature of less than 200 °C which is suggested to be due to the lack of Lewis acid sites, as determined from NH3-TPD (temperature program desorption) analysis. Future work to lower the SCR reaction temperature with high NO_x efficiency is suggested.