Catalytic removal of phenol from gas streams by perovskite-type catalysts

Three perovskite-type catalysts prepared by citric acid method are applied to remove phenol from gas streams with the total flow rate of 300 mL/min, corresponding to a GHSV of10,000/hr. LaMnO3 catalyst is first prepared and further partially substituted with Sr and Cu to prepare La0.8Sr0.2MnO3 and La0.8Sr0.2Mn0.8Cu0.2O3, and catalytic activities and fundamental characteristics of these three catalysts are compared. The results show that phenol removal efficiency achieved with La0.8Sr0.2Mn0.8Cu0.2O3 reaches 100% with the operating temperature of 200°C and the rate of mineralization at 300°C is up to 100%, while the phenol removal efficiencies achieved with La0.8Sr0.2MnO3 and LaMnO3 are up to 100% with the operating temperature of 300°C and 400°C, respectively. X-ray photoelectron spectroscopy（XPS） analysis shows that the addition of Sr and Cu increases the lattice oxygen of La0.8Sr0.2Mn0.8Cu0.2O3, and further increases mobility or availability of lattice oxygen. The results indicate that La0.8Sr0.2Mn0.8Cu0.2O3 has the best activity for phenol removal among three catalysts prepared and the catalytic activity of phenol oxidation is enhanced by the introduction of Sr and Cu into LaMnO3. Apparent activation energy of 48 k J/mol is calculated by Mars–Van Krevelen Model for phenol oxidation with La0.8Sr0.2Mn0.8Cu0.2O3 as catalyst.