硬模板法制备大比表面积钼酸钴及其有氧氧化脱硫性能

PREPARATION OF COBALT MOLYBDATE WITH LARGE SPECIFIC SURFACE AREA AND ITS AEROBIC OXIDATION DESULFURIZATION PERFORMANCE

以氯化钴和钼酸铵为原料、KIT-6为硬模板,结合碱蚀过程制备了大比表面积的钼酸钴催化剂。通过X射线衍射、扫描电子显微镜、X射线光电子能谱和N_(2)吸附-脱附技术确定了催化剂的形貌和结构特征。以介孔钼酸钴为催化剂、O_(2)为氧化剂,氧化脱除模拟油中的二苯并噻吩。考察反应温度、O_(2)流量、催化剂加入量以及硫化物种类对脱硫率的影响。试验结果表明,最佳的反应条件如下:模拟油量为20 mL,催化剂加入量为0.05 g,O_(2)通入流量为200 mL/min,反应温度为110℃,反应时间为60 min。在此条件下脱硫率可以达到96.2%,催化剂重复使用5次后活性没有明显降低。机理研究结果表明,在催化剂作用下形成的超氧自由基是催化剂具有较高脱硫活性的关键。

Cobalt molybdate catalyst with large specific surface area was prepared fromcobalt(II)chloride and ammonium molybdate with KIT-6 as hard template and alkali etching process.The morphology and structural of the catalyst were characterizedby X-ray diffractometer,scanning electron microscope,X-ray photoelectron spectroscopy,and N_(2) adsorption desorption techniques.Using cobalt molybdate as catalyst and O_(2) as oxidant,the catalytic oxidation of dibenzothiophene from simulated oil was studied.The effects of reaction temperature,O_(2) flow rate,the amount of catalyst addition and sulfide type on desulfurization efficiency were investigated.The results showed that the optimal reaction conditions were as follows:a simulated oil amount of 20 mL,an amount of catalyst of 0.05 g,an O_(2) flow rate of 200 mL/min,a reaction temperature of 110℃and a reaction time of 60 min.Under this condition,the desulfurization rate could reach 96.2%,and the activity of the catalyst had not significantly decreased after 5 times of reuse.Mechanism studies showed that the formation of superoxide radicals in the presence of catalystwas the key to the high desulfurization activity of the catalyst.