CeCoaOx catalysts derived from metal-organic frameworks for enhancing catalytic toluene oxidation by tuning surface oxygen property
Xinxin Jin, Dong Liu, Shaokai Hou, Qinghao Ge, Zhihao Zhao, Zhiping Zhang, Yujun Zhu
Abstract
Rod-shaped CeCo a O x catalysts with varying Co doping ratios (a = 0.012, 0.017, 0.022) were synthesized by calcinating the Ce-MOF, prepared using a water bath and trimesic acid as an organic ligand. This method ensured a high degree of elemental mixing, abundant pore channels and a large specific surface area are all beneficial for enhancing toluene catalytic oxidation activity. Raman, XPS, and catalytic activity tests confirmed strong interactions between the Ce and Co oxides, promoting the formation of more Ce 3+ and oxygen vacancies. Among these catalysts, CeCo 0.012 O x exhibited superior catalytic performance for toluene oxidation under weight hourly space velocity of 40,000 mL·g −1 ·h −1 . The temperature at toluene conversion of 10 %, 50 % and 90 % was 140, 205 and 226 °C, respectively, which was 61, 12 and 14 °C higher than those over pure phase CeO 2 . CeCo 0.012 O x also demonstrated excellent activity stability under high humidity (10 vol%H 2 O). H 2 -TPR, O 2 -TPD and in situ DRIFTS also revealed that surface-absorbed oxygen species played a crucial role in catalytic activity, with CeCo 0.012 O x benefiting from abundant oxygen vacancies and effective oxygen species mobility.