Influence of Ga doped CoMo/Al2O3 catalysts on the selective hydrogenation performance of polycyclic aromatic hydrocarbons

It is a challenge to effectively control the intermediate ring hydrogenation products in tricyclic aromatic hydrocracking reactions in order to further increase the selectivity of BTX. A series of doped gallium modified CoMo/Al2O3 catalysts were prepared, the effect of gallium on the catalyst's physicochemical properties, active phase structure and hydrogenation reaction pathway was studied. The study revealed that the doping of gallium species promoted the sulfidation of Mo species and improved the catalytic activity of the catalyst. The 1 % Gamodified catalyst showed the best selective hydrogenation performance, in which the conversion rate of phenanthrene was up to 83.75 % and the selectivity for dihydrophenanthrene reached 28.60 %. In addition, DFT calculations show that the introduction of Ga into the active phase between the Co and Mo atoms results in a higher differential charge density in the middle ring, which is more conducive to hydrogen adsorption.