Template and interfacial reaction engaged synthesis of CeMnOx hollow nanospheres and their performance for toluene oxidation

A series of well-dispersed CeMnO x hollow nanospheres with uniform diameter and thickness were synthesized by a novel approach combining the template method and interfacial reaction. A SiO2 template was used as a hard template for preparation of SiO2@CeO2 nanospheres by solvothermal reaction. SiO2@CeMnO x could be formed after KMnO4 was reacted with SiO2@CeO2 by interfacial reaction between MnO4- and Ce3+. Among all the prepared catalysts, CeMnO x -3 with a moderate content of Mn (15 wt%) exhibited the lowest temperature for complete combustion of toluene (280 °C). Moreover, it showed high stability for 36 h with toluene conversion above 97.7% and good water tolerance with 5 vol% H2O. With characterization, we found that the reaction between Ce and Mn in the Ce-Mn binary oxides gave rise to increased Ce3+ and oxygen vacancies, which led to the formation of enhanced reducibility and more surface-absorbed oxygens (O22-, O2- and O-), and improved the catalytic performance further.