Promoting effects of ZrO₂ modification on Ni/SBA-15 catalysts for dibenzofuran hydrodeoxygenation

The performance of the ZrO₂ 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 ZrO₂ modification on the structural characteristics and reaction activity of Ni/Zr-SBA-15 catalysts were analyzed. The results showed that the addition of ZrO₂ 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 ZrO₂ (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 ZrO₂ were 10% and 20%, respectively. Both values were much higher than those on the unmodified Ni/SBA-15 catalyst.