Structure-activity relationship for trimetallic CuCoZr catalyst in hydrogenolysis of furfural to 1,5-pentanediol

Selective hydrogenolysis of the furanic C-O bond in biomass-derived furfural (FF) to produce pentanediol (PDO) requires activation of multiple functional groups for synthesizing biodegradable polyester monomers. Herein, selective conversion of FF to pentanediols is demonstrated over a Zr-modified CuCo catalyst to achieve a PDO yield of 61.2 % (48.6 % 1,5-PDO and 12.6 % 1,2-PDO). Incorporation of Zr adjusts electron transfer and metal-metal interactions in CuCo materials, enhancing the density of surface oxygen vacancies (Ov_s) and CoO_x species, as well as facilitating the formation of ZrO₂/Co₃O₄-Ov_s interfacial sites. The catalytic mechanism involves sequential steps: (1) H₂ adsorption and dissociation at Cu⁰ sites, followed by hydrogen spillover to adjacent ZrO₂/Co₃O₄-Ov_s sites; (2) selective hydrogenation of the aldehyde group in Ov-adsorbed/activated FF to form furfuryl alcohol (FFA); and (3) cooperation between acid sites and Ov_s to weaken the furanic C-O bond, enabling its cleavage via hydrogen attack to yield 1,5-PDO. The mechanistic role of zirconia in the CuCoZr catalyst is to tune oxygen vacancies and acid-base properties of CuCo thus providing a basis for designing zirconia-integrated catalysts.