Promotional Role of Surface Defects on Carbon-Supported Ruthenium-Based Catalysts in the Transfer Hydrogenation of Furfural

The synthesis of highly efficient supported metal catalysts is of vital importance for the modern development of the production of chemicals. In this regard, biomass-based chemical transformation holds potential promise through many heterogeneous catalytic processes. Herein, we report surface defect engineering on a carbon-supported, Ru-based catalyst by a twostep hybridization-self-reduction route, which involves the assembly of a hybrid composite of ternary Co-Al-Ru layered double hydroxide (CoAlRu-LDH) and amorphous carbon through the carbonization of glucose and a subsequent in situ self-reduction process. The results revealed that Ru3+ species in the resulting CoAlRu-LDH-C composite could be reduced in situ to Ru-0 species by the carbon component in the hybrid composite, and Co-containing spinels with a large quantity of surface oxygen vacancies could be formed simultaneously on the surface. The as-fabricated Ru-based catalyst showed a superior catalytic performance in the liquid-phase transfer hydrogenation of furfural to furfuryl alcohol using benzyl alcohol as hydrogen donator to other Ru-based catalysts derived from LDHC composite precursors. It was proven that surface defects (i.e., oxygen vacancies, Co2+ species) could enable the chemisorption of furfural spatially and ensure the activation of its carbonyl groups, which promoted the transfer hydrogenation greatly.