Investigation of RuOx doping stimulated the high catalytic activity of CeOx-MnOx/TiO2 catalysts in the NH3-SCR reaction: Structure-activity relationship and reaction mechanism

CeOx-MnOx/TiO2 (CMT) is the prototype, low-temperature (150–250 ℃) mixed oxide NH3-deNOx catalyst with the greatest potential for industrial application. The improvement of ultra-low temperature (60–150 ℃) denitration activity, SO2 and alkali resistance of CMT catalysts received significant attention. RuOx has been widely utilized in selective catalytic oxidation (SCO), and we believe that the catalyst must first undergo SCO before selective catalytic reduction (SCR). Therefore, a series of RuOx-CMT catalysts were prepared by impregnating RuOx with CMT as the carrier and their catalytic mechanism at low temperature and activity analyzed in detail through XRF, XRD, BET, TEM, HRTEM, STEM+EDS, XPS, H2-TPR, NH3-TPD-MS and in situ DRIFTS characterizations. The obtained results show that RuOx modification significantly improved the low-temperature denitrification activity of CMT by enhancing the interaction of Ce, Mn and Ti, promoting the conversion of inactive bidentate nitrate to the active monodentate nitrate and strengthening the Mars-van Krevelen (M-K), Langmuir-Hinshelwood (L-H), and Eley-Rideal (E-R) mechanisms.