制备参数对β-Mo2N0.78催化剂加氢脱硫活性影响的研究

以N2与H2的混合气为反应气，和三氧化钼进行多段程序升温反应，制得一种β晶型的氮化钼。以噻吩为模型化合物的常压加氢脱硫反应表明，β-Mo2N0.78具有较强的加氢脱硫活性和强的抗硫化性能。同时考察了预还原、反应温度以及氮化末温、升温速率、反应气中N2-H2比及氮化时间等制备参数对β-Mo2N0.78加氢脱硫活性的影响。研究发现，β-Mo2N0.78的加氢脱硫活性在320 ℃～400 ℃随反应温度的升高增强，而还原预处理会降低催化剂的活性。氮化末温、氮化时间、反应气组成和升温速率等制备参数对催化剂的活性有明显的影响：随着氮化末温的升高，所制备的催化剂催化加氢脱硫活性降低；在氮化末温恒温较长时间，可以引起制备催化剂的加氢脱硫活性下降；存在最佳的反应气组成和各段升温速率。小晶粒的β-Mo2N0.78具有强的加氢脱硫活性。

INFLUENCE OF THE PREPARATION PARAMETERS OF β-Mo2N0.78 CATALYSTS ON ITS HYDRODESULFURIZATION ACTIVITY

β-Mo2N0.78 was synthesized using the reaction of molybdloum oxide with N2-H2 via temperature-programmed reaction. Thiophen hydrodesulfurization(HDS) overβ-Mo2N0.78 was carried out at atmosphere pressure. The results showed that the HDS activity increased with increasing reaction temperature, and pre-reduction could deactivate the catalytic activityβ-Mo2N0.78 also had a resistance to sulfurization. The bulk structure of catalysts did not change after long time HDS reaction. Influence of the synthesis factors including nitriding temperature, nitriding time, N2-H2 ratio and temperature program of nitriding reaction on HDS activity of β-Mo2N0.78 was investigated in detail: (1) the catalytic activity of catalyst decreased with the increasing of nitriding final temperature; (2) the catalyst which was nitrided for a long time at final temperature has low HDS activity; (3) a suitable N2-H2 ratio and a temperature program of nitriding reaction to synthesize catalyst with high HDS activity were determined. It was found that small crystallites of molybdenum nitride had high catalytic activity.