Perovskite hollow nanospheres for the catalytic wet air oxidation of lignin

A urea-assisted solvothermal-calcination method was used to prepare LaFexMn1-xO3 and La0.9Sr0.1MnO3 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 degrees 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. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.