- 學位論文
擔載Co/Mo觸媒於含釩化物載體上進行深度加氫脫硫之研究
Deep Hydrodesulfurization over Co/Mo Catalysts Supported on Oxides Containing Vanadium
摘要
使用含浸釩的鹽類來進行修飾TiO2-ZrO2與γ-Al2O3載體。在dibenzothiophene (DBT)與4,6-dimethyldibenzothiophene (46DMDBT)的加氫脫硫實驗中，此類釩修飾過的觸媒展現出良好的氫化途徑的選擇性。以CoMo/(V2O5/TiO2-ZrO2)觸媒對DBT進行加氫脫硫時，氫化途徑(HYD)與直接脫硫途徑(DDS)的比值為3.1；而相同條件下，在CoMo/(V2O5/γ-Al2O3)上，HYD/DDS則是為0.9。此時CoMo/γ-Al2O3上的值則僅為0.2。雖然DBT在CoMo/γ-Al2O3觸媒上的活性是高於在CoMo/(V2O5/TiO2-ZrO2)觸媒上。但是以46DMDBT為反應物時，卻得到相反的結果。主要是因為此修飾過的觸媒具有較高的氫化能力，並且含浸的釩與載體本身具有的較多與較酸的酸性點也會幫助46DMDBT的反應。 在TPR的實驗中指出：CoO-MoO3在TiO2-ZrO2與V2O5修飾的載體上是比較容易被還原的。這代表著觸媒與載體間作用力的不同，因此可能形成與γ-Al2O3載體上不同的觸媒形貌：一些具有氫化活性點的單層或是較薄的結構。此外，XPS的結果則顯示出，含浸的釩會影響到MoS2與載體間的作用力。而在這二元的V-Mo硫化物上所產生的synergetic effect，可以促使觸媒的反應活性點更容易以HYD途徑進行加氫脫硫。
並列摘要
TiO2-ZrO2 and γ-Al2O3 supports were modified by impregnation with a vanadium salt. The hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (46DMDBT) showed that the selectivity of the hydrogenation (HYD) pathway was greatly increased by this modification. The ratio of HYD to direct desulfurization (DDS) pathway in the HDS of DBT over CoMo/(V2O5/TiO2-ZrO2) was 3.1 and over CoMo/(V2O5/γ-Al2O3) it was 0.9. The reactivity of DBT over CoMo/γ-Al2O3 was higher than that over CoMo/(V2O5/TiO2-ZrO2), while the opposite was true for the reactivity of 46DMDBT, which was due to the higher hydrogenation activity, and the more acidic sites of the impregnated V2O5 and the mixed metal-oxides supports. Temperature-programmed reduction indicated that CoO-MoO3 on the TiO2-ZrO2 and V2O5 modified supports was more reducible and possibly has a different morphology than on γ-Al2O3. Furthermore, the results of X-ray photoelectron spectroscopy indicated that the impregnated V2O5 affected the interaction between MoS2 and the supports. Thus, the synergetic effect of binary V-Mo sulfides could induce active sites to facilitate the HYD pathway.