Perovskite hollow nanospheres for the catalytic wet air oxidation of lignin

Abstract

A urea-assisted solvothermal-calcination method was used to prepare LaFe x Mn 1- x O 3 and La 0.9 Sr 0.1 MnO 3 hollow nanospheres, and their crystal phase, morphology, and specific surface area properties were analyzed by X-ray diffraction, transmission electron microscopy, and nitrogen adsorption-desorption isotherms. These materials were then evaluated as catalysts for the catalytic wet air oxidation (CWAO) of lignin, and showed much better catalytic performance than perovskite prepared by the traditional sol-gel method. The structure of the hollow nanospheres has been suggested as the reason of this higher catalytic activity. For the CWAO reaction at 120 °C and 0.2 MPa O 2 , the conversion of lignin was greater than 80% after 1 h. Analysis of the ions leaching from the material following the completion of the reaction showed that the catalysts were very stable under the reaction conditions because of their perovskite phase structure. Perovskite hollow nanospheres have been used as catalysts for the CWAO of lignin, where they exhibited good catalytic activity and excellent stability, revealing a new application in biomass conversion.