Catalytic performances of SmCoO3 perovskite-type catalysts supported on cordierite in volatile organic pollutant oxidation

The Co-based perovskite-type catalysts exhibited excellent performance in catalytic oxidation of VOCs and could provide more Co oxidation states. The rare earth element Sm has a strong oxygen storage capacity and can enhance oxygen trapping in catalytic reactions. B-site doping can induce the formation of structural defects (anionic or cationic vacancies) and various states of oxidation, which can further enhance the catalytic activity. The catalytic oxidation of toluene was conducted using SmCoO3 and SmCo0.8B0.2O3 (B = Cu, Fe, or Ni) perovskite-type oxides supported on cordierite honeycomb (CC) and synthesized using a citric acid complex-impregnation method. Substituting Co with Cu improved the catalytic performance in toluene oxidation. The order of the catalytic activities in toluene removal was as follows—SmCo0.8Cu0.2O3/CC > SmCoO3/CC > SmCo0.8Fe0.2O3/CC > SmCo0.8Ni0.2O3/CC—based on temperatures corresponding to 50 % and 90 % toluene conversion at a specific toluene concentration. The high catalytic capacity of SmCo0.8Cu0.2O3/CC was attributed to its higher adsorbed O concentration (Oads/O = 0.80) and surface Co3+/Co2+ ratio (16.50), as well as optimal low-temperature reducibility (H2 consumption = 0.40 mmol/g, below 250 °C). Thus, this study provides an effective method for identifying highly active catalysts and removing air pollutants.