Promotional effect of Co and Ni on MoO3 catalysts for hydrogenolysis of dibenzofuran to biphenyl under atmospheric hydrogen pressure

Co(Ni)/MoO 3 catalysts were prepared, characterized and evaluated for the hydrogenolysis of bio-derived dibenzofuran (DBF), aiming at the understanding of the promoting effect of Co/Ni on MoO 3 for high-yield production of aromatic products. All Co(Ni)/MoO 3 catalysts selectively cleaved C-O bond, thus effectively transformed DBF to biphenyl (BP) at relatively moderate conditions. The experimental results from varying Mo species by adjusting the reduction temperature of MoO 3 together with XPS and in-situ XRD characteristic were evident that Mo 5+ species was responsible as the major active specie for the reaction. Promotional effect between Co(Ni) and Mo in Co(Ni)/MoO 3 catalysts was observed, resulted from the presence of acidic Co(Ni)MoO 4 species and a large number of Mo 5+ species both of which were created local to the Co(Ni)-O-Mo interface, as can be characterized by in-situ XRD, XPS, H 2 -TPR, NH 3 -TPD, in-situ FT-IR, Raman and TEM. The trend of the initial reaction rate follows: MoO 3 (0.18 μmol∙g cat −1 ∙s −1 ) < Ni/MoO 3 (0.26 μmol∙g cat −1 ∙s −1 ) < Co/MoO 3 (0.29 μmol∙g cat −1 ∙s −1 ), corresponding to the decreasing activation barrier. And the best catalytic activity was observed for the 100% yield of BP over Co/MoO 3 . A possible mechanism, including Co(Ni) facilitated reduction of Mo 6+ to Mo 5+ and Co(Ni) enhanced formation of acidic sites, is proposed to be responsible for the high activity in Co(Ni)/MoO 3 catalysts.