Highly selective hydrogenolysis of furfuryl alcohol to 1,5-pentanediol over an efficient Ni/PrO_x catalyst

The catalytic conversion of biomass-derived furfural and its derivatives such as furfuryl alcohol (FFA) into high value-added chemicals has been the subject of considerable attention within the field of biomass refining. Nevertheless, the selective hydrogenolysis of FFA represents a significant challenge to obtain the goal product such as 1,2-pentanediol (1,2-PeD) or 1,5-pentanediol (1,5-PeD) with satisfactory yield, due to complicated network involved in the FFA hydrogenolysis. Hence, selectivity control is the key to the hydrogenolysis of FFA. In this work, a 45Ni-Pr (45 wt% Ni/PrO_x) catalyst prepared using a facile sol–gel method behaved very well in the hydrogenolysis of FFA, resulting in up to 86.3 % yield of 1,5-PeD under mild reaction conditions. Introduction of PrO_x enhanced Ni dispersion and promoted intimate contact between Ni species and PrO_x. This created weak and medium-strong basicity and oxygen vacancies on the catalyst surface, which facilitated the adsorption of FFA via the C-O-C bond on the furan ring and C-OH at the side chain. Moreover, the 45Ni-Pr catalyst had the balanced Ni⁰ and Ni²⁺ sites, which guarantee not only the saturation of the C=C bond on the furan ring in the presence of Ni⁰ sites to yield the intermediate tetrahydrofurfuryl alcohol (THFA), but also the subsequent ring-opening hydrogenolysis of THFA at the Ni⁰-O_V-Ni²⁺-PrO_x interfacial sites to produce 1,5-PeD selectively. This work establishes a viable and environmental benign approach for producing 1,5-PeD from the bio-based furfural derivatives, as well as a reference for the selective ring-opening hydrogenolysis of furan compounds.