过渡金属碳化物具有类似贵金属的电子结构和加氢性能。采用等体积浸渍法制备了不同Ni/W比的NiW/γ-Al₂O₃催化剂,以程序升温碳化法转化为NiW碳化物后对芳烃模型化合物和低温煤焦油中分离所得芳烃组分进行加氢处理。催化剂的N₂吸附、XRD、H₂-TPR和SEM表征表明,Ni的添加促进了载体表面WO₃物种的分散和还原,抑制了WO₃晶体的团聚和大晶粒的生成。萘的加氢实验表明,Ni/W原子比为0.6时催化剂的活性最佳,而添加苯酚和吡啶后的模型油加氢过程中萘的转化率和十氢萘的产率均明显下降,Ni/W原子比为0.47和0.6的催化剂性能相近,煤焦油中芳烃组分加氢后Ni/W原子比为0.47的催化剂性能更优。结果表明,Ni和W均具有良好的加氢活性,但Ni耐杂原子性能较差,二者存在一个最佳的配比以使加氢性能更优。有杂原子化合物存在时,如煤基芳烃组分的加氢,Ni/W原子比为0.47的NiW碳化物催化剂具有更好的加氢性能。

Transition metal carbides have similar electron structure and hydrogenation performance with noble metal.NiW/γ-Al₂O₃ catalysts with different Ni/W ratio were prepared by equi-volumetic impregnation method,and then the samples were converted to carbides by temperature programed carburization and used for hydroprocessing of aromatic model compounds and aromatic fraction separated from low temperature coal tar.Results of N₂ adsorption,XRD,H₂-TPR and SEM showed that Ni addition promoted the dispersion and reduction of WO₃ species on the support surface,inhibited the aggregation of WO₃ crystals to form large particles.The hydrogenation results of naphthalene showed that the activity of catalyst with Ni/W atomic ratio of 0.6 was the best,while the naphthalene conversion and decalin yield reduced obviously after phenol and pyridine were added in the model oil,which resulted the catalysts with Ni/W atomic ratio of 0.47 and 0.6 showed similar performance.The one with Ni/W atomic ratio of 0.47 showed the better performance for hydroprocessing of the aromatic fraction separated from coal tar.The results showed that Ni and W were both active for hydrogenation,however,Ni was less resistant to heteroa-toms,thus the hydrogenation performance for NiW catalyst was the best with the optimal Ni/W ratio.With the present of heteroatomic compounds,such as coal-derived aromatic fraction,NiW carbide catalyst with Ni/W atomic ratio of 0.47 showed the best performance.