| 초록 |
The structure sensitivity of Cu based catalysts has been an important issue in methanol synthesis. It was claimed that the methanol synthesis was structure-insensitive by showing that methanol synthesis rates were linearly proportional to Cu surface areas using Cu/ZnO/Al2O3. On the other hand, the formate species and hydrogen spillover from Cu to ZnO and ZrO2 were also observed and it was suggested that the formate species were hydrogenated on ZnO and ZrO2. The observation of hydrogen spillover shows that methanol synthesis can occur on ZrO2. The Cu surface areas of Cu/ZnO/Al2O3 catalysts were 10.6, 13.0, 22.6, 27.9, 30.6, 27.7 and 21.9 m2/g, depending on the aging time of 6, 12, 18, 24, 36, 42 and 72 h. The Methanol TOF (MeOH mmol/Cu-m2/h) for seven catalysts was within 2.67±0.27 MeOH mmol/Cu-m2/h, indicating that methanol synthesis on Cu/ZnO/Al2O3 catalysts is structure-insensitive. On the other hand, MeOH TOF increased with a ZrO2 addition to Cu/ZnO/Al2O3. This experimental results suggests that ZrO2 can afford active sites for methanol synthesis. |
