The catalytic oxidation performance of toluene over the Ce-Mn-Ox catalysts: Effect of synthetic routes

Ce-Mn-O-x, catalysts were synthesized by impregnation (CM-IM), co-precipitation (CM-CP), citrate sol-gel (CM-SG) and hydrothermal (CM-HT) methods. The synthesis methods exhibited a great impact on the physicochemical properties of catalysts, resulting in different catalytic activity. The catalytic oxidation activity of toluene followed the sequence: CM-HT (T-50: 234 degrees C; T-90: 246 degrees C) > CM-SG (T-50: 242 degrees C; T-90: 249 degrees C) > CM-CP (T-50: 243 degrees C; T-90: 259 degrees C) > CM-IM (T-50: 251 degrees C; T-90: 261 degrees C), which was consistent with the sequence of surface relative percentage of C-ov, Ce3+, Mn3+, O-alpha, and r values. Among them, CM-HT showed the best catalytic oxidation performance of toluene due to more structural defects, oxygen vacancies, surface adsorption oxygen, normalized conversion rate and other active species. In addition, CM-HT catalysts showed reliable water resistance and good durability, implying the potential industrial application. (C) 2019 Elsevier Inc. All rights reserved.