Interaction of Ethanol with MgO-SiO2 Catalysts Studied by TPD Techniques

A series of MgO-SiO2 catalysts were prepared by physical mixture (PM), sol-gel (SG), incipient wetness impregnation (IWI) and wet-kneading (WK) methods. The interaction of ethanol with MgO, SiO2 and as-prepared MgO-SiO2 catalysts surfaces was studied using temperature programmed desorption (TPD) in order to determine the dependence of the reaction pathways on surface acid–base property of these catalysts synthesized by different methods. Dehydrogenation and dehydration reactions occur competitively over the surface of MgO-SiO2 catalysts, depending on the surface acid-base nature of the catalysts. Our results indicated that MgO-SiO2-WK has excellent dehydrogenation ability among these catalysts, which is a critical step in transforming ethanol into 1,3-butadiene (1,3-BD), and those catalysts possessing more acidic sites are more favorable for ethylene formation via ethanol dehydration. The results obtained are also consistent with our previous finding that surface acid-base properties of catalysts is a key...