ZrO_(2)改性对Ni/SBA-15催化二苯并呋喃加氢脱氧的促进作用研究

Promoting effects of ZrO_(2) modification on Ni/SBA-15 catalysts for dibenzofuran hydrodeoxygenation

以二苯并呋喃为煤焦油中含氧组分的模型化合物,在280℃、氢气压力6.5 MPa条件下于反应釜中考察了Ni/Zr-SBA-15催化剂的加氢脱氧性能,分析了ZrO_(2)改性对Ni/SBA-15催化剂结构特性与反应活性的影响。结果表明,ZrO_(2)的添加会增强活性金属Ni与载体间相互作用,促进Ni颗粒的分散,同时会在催化剂中引入氧空位,氧空位与活性金属Ni的协同作用可以促进含氧中间产物的转化,提高目标产物联环己烷的收率。但过量ZrO_(2)(30%)的添加会降低催化剂的比表面积、孔容,不利于Ni颗粒分散,不利于反应的进行。研究发现,当ZrO_(2)添加量为10%时,二苯并呋喃反应速率最高,为9.21 mmol/(min·g);当ZrO_(2)添加量为20%时联环己烷生成速率最高,为3.74 mmol/(min·g);两者均高于未改性的Ni/SBA-15催化剂。

The performance of the ZrO_(2)modified Ni/SBA-15 catalysts was investigated for the hydrodeoxygenation of dibenzofuran as a coal tar model compound in an autoclave at 280℃and a hydrogen pressure of 6.5 MPa.The effects of ZrO_(2)modification on the structural characteristics and reaction activity of Ni/Zr-SBA-15 catalysts were analyzed.The results showed that the addition of ZrO_(2)increased the interaction between the active metal Ni and the SBA-15 support,promoted the dispersion of Ni particles,and introduced oxygen vacancies in the catalysts.As a result,the conversion of oxygen-containing intermediates was enhanced,and thereby the yield of the target product bicyclohexane was improved.However,the addition of excessive ZrO_(2)(30%)could reduce the specific surface area and pore volume of the catalysts and cover Ni surface,which was not conducive to the reaction.The study found that the highest dibenzofuran conversion rate of 9.21 mmol/(min·g)and the highest bicyclohexane formation rate of 3.74 mmol/(min·g)were achieved when the addition amount of ZrO_(2)were 10%and 20%,respectively.Both values were much higher than those on the unmodified Ni/SBA-15 catalyst.