Insight into the role of TiO2 modified activated carbon fibers for the enhanced performance in low-temperature NH3-SCR

TiO2-modified activated carbon fiber (ACF) was prepared by a dip-coating method, and supported with CeO2 nanoparticles. The catalysts were applied in the low temperature selective catalytic reduction (SCR) of NO for the first time and exhibited significantly higher NO conversion than the unmodified catalyst in the entire temperature range. Different characterizations were carried out to show that the redox and acidic properties were closely related to the superior catalytic performance. Furthermore, the promotional mechanism was elucidated from the changes in the structure and surface properties of catalysts. It was verified that the introduction of TiO2 not only enhanced the concentration of surface chemisorbed oxygen and surface Ce3+ but also improved the adsorption and activation of NH3 and NO, thus more-NH2 and nitrate species were generated to participate in SCR reaction, which was attributed to a synergistic interaction between TiO2 and CeO2.