Confined nanoreactor for synthesis of MnCe composite oxide nanowires with enhanced catalytic activity towards aromatic VOCs oxidation

Abstract

A novel Mn–Ce composite oxide nanowires (MnCe-NWs) catalyst with a high specific surface area has been successfully fabricated via restricting the growth of nanocrystal within a confined nanoreactor offered by the Santa Barbara Amorphous-15 (SBA-15) template. The characterizations of X‐ray diffraction (XRD), N 2 adsorption-desorption, and Energy Dispersive X-Ray mapping (EDX-mapping) showed the Mn–Ce oxide nanowires generated in a confined nanoreactor had a homogeneous cubic fluorite structure with good metal distribution and high porosity. The X‐ray photoelectron spectroscopy (XPS), Raman, H 2 temperature-programmed reaction (H 2 -TPR), and O 2 temperature‐programmed desorption (O 2 -TPD) determined that the Mn–Ce oxide nanowire increased the lattice defects, active oxygen species, and reducibility compared to the one (MnCe-DC) generated by direct calcination in open space. Owing to these excellent properties, the Mn–Ce oxide nanowire exhibited much better catalytic performance in both toluene and benzene oxidation. The conversion efficiency of toluene and benzene can reach 90% at 199 °C and 211 °C over MnCe-NWs (100 ppm, space velocity = 60,000 mL g −1 h −1 ) while the corresponding temperature increased by 30 and 52 °C respectively over MnCe-DC. The influence of space velocity and concentration of toluene/benzene on the catalytic oxidation of toluene/benzene has also been investigated. The catalytic oxidation mechanisms of toluene/benzene and main intermediates are deduced based on the meditator of the reactions. Moreover, the durability test and the water effect test demonstrated that it has remarkable stability and high toleration of high moisture.