Preparation Of Transition Metal Phos Phide On Modified Al₂O₃

With the demand of the industrial development improving, more efficient and less cost catalyst in hydrofining field is eagerly needed. Because of the outstanding performance of the transition metal phosphide catalyst, it's under a high expectation. As it has deep hydrogenation activity and great sulfur tolerance, it's broadly studied in HDS and HDN field and applied in aerospace and material field. However, the preparation of transition metal phosphide catalyst, especially supported catalyst, is still a difficult problem. It has been a barrier for further development. Specifically, the problem include high cost on preparation and rigor conditions.The supported transition metal phosphide uses SiO2 that has weak interaction force with P in many literatures. Using Al2O3, which broadly applied on industry, as a carrier to support transition metal phosphide during the preoperational process, the production of AIPO4 makes the process more difficult. So, modified-Al2O3 and using low valence phosphorus source can solve the difficult problem on the preparation.In this paper, we used solvothermal method, low-temperature combustion synthesis method and coprecipitation method to prepare Al2O3(syn), Ce-Al2O3 and Ti-Al2O3 separately. And we mainly used (NH4)2HPO4 as phosphorus source to prepare catalyst with equivalent-volume impregnation method. We used phosphorous acid that had lower valence state as phosphorus source for preparation of CoP. Thus, the preparation process was simplified and the reduction temperature was fell off. Then, we used XRD, N2 absorption and NMR to represent modified-Al2O3 and catalyst. Finally, we used DBT as sulfocompound (reaction temperature was 280-360?, reaction pressure was 4 MPa) to observe HDS performance on the catalyst.As for preparation, XRD pattern of catalyst and NMR of Al2O3 indicated that Ce-Al2O2 and Al2O3(syn), the two kinds of modified-Al2O3, had a lot of Alvwhile it was only has a little on Ti-Al2O3, and industrial ?-Al2O3 didn't contain Al, and it showed that changing the structure of Al2O3 and introducing modification reagent can prepare modified-Al2O3 with Alv. For Ce-Al2O3 and Al2O3(syn), it can carry phosphide with lower P/M compared with Ti-Al2O3, which needed to increase loadings and higher P/M. And ?-Al2O3 was hard to carry phosphide. It strongly indicated that Alv has weak acting force with P element and difficult to produce AlPO4. In this way, we promoted the production process of transition metal phosphide.HDS reaction result indicated that the reaction reactivity of the catalyst on Al2O3 was higher than bulk catalyst. Also the reaction reactivity of the catalyst supported Ce-Al2O3 was slightly higher than the catalyst without Ce, due to introducing Ce. Finally, the selectivity of DDS on the catalyst supported Al2O3 was higher than the catalyst supported SiO2. In conclusion, it illustrated the different carriers had a certain impact in HDS reaction performance.