| 초록 |
We synthesized aluminas with different facet ratio (platelet and rod-shape) and evaluated facet-dependent activity over ethanol dehydration. Platelet- and rod-shaped alumina were characterized by XRD, BET, TEM and ethanol temperature programmed desorption (TPD). Platelet and rod γ-Al2O3 showed identical surface characteristics with commercial and similar activities over ethanol dehydration. After 1100oC calcination, commercial γ-Al2O3 transformed into α-Al2O3. However, platelet transformed into θ-phase while the rod into the δ-phase after same treatments. Interestingly, Ethanol TPD showed significantly different desorption profiles which suggest different surface characteristic despite similar BET surface area. Their maximum desorption rate showed rod ＞ platelet ＞ commercial order and their ethanol dehydration activity also showed the same trend. All results suggest morphology-dependent phase transformation which led to different activity over ethanol dehydration. |
