The effect of potassium modification on structural properties and catalytic activity of copper and iron containing SBA-16 catalysts for selective oxidation of ethanol

Copper and iron SBA-16 catalysts were synthesized using hydrothermal method and modified with potassium. XRD patterns showed that characteristic peaks of SBA-16 for all catalysts did not destroy with metal loading. The metal and potassium loading to SBA-16 structure led to generally the decreasing of specific surface area values. While total pore volume value of SBA-16 increased with copper loading, it decreased with iron loading. Pore diameter values of SBA-16 generally increased with metal loading. It was seen that from TEM images metals settled as nanoparticles to the SBA-16 structure. EDX results demonstrated that potassium modification treatment increased especially the success of metal loading. FTIR spectrums of all catalysts exhibited the characteristic structural bands of SBA-16. It was seen that the peak intensity of both Bronsted and Bronsted + Lewis acid sites of the SBA-16 increased by the metal loading. On the other hand potassium modification improved the acid sites. UV-Vis DR and XPS spectra showed that copper and iron species settled as Cu + 2 and Fe + 3 form, respectively. The potassium modified catalysts exhibited the highest conversion of 77% and acetaldehyde selectivity of 81% compared to catalysts without potassium modification at reaction temperature of 350 degrees C.