Selective hydrogenation of glucose to sorbitol with tannic acid-based porous carbon sphere supported Ni-Ru bimetallic catalysts

Ni-Ru bimetallic porous carbon sphere (Ni-Ru@PCS) catalysts were synthesized via formaldehyde-assisted, metal-coordinated crosslinking sol-gel chemistry, in which biomass-derived tannic acid and F127 surfactant were used as carbon precursor and soft template, respectively, and Ni²⁺ and Ru³⁺ were used as cross-linkers. In the developed method, Ni-Ru particles became uniformly dispersed in the carbon skeleton due to strong coordination bonds between metal ions (Ni²⁺ and Ru³⁺) and tannic acid molecules and bimetal interactions. The as-synthesized Ni-Ru_10:1@PCS catalyst with a loading Ni:Ru mole ratio of 10:1 was applied for the selective hydrogenation of glucose to sorbitol, and provided 99% glucose conversion with a sorbitol selectivity of 100% at 140 ℃ in 150 min reaction time and exhibited good stability and recyclability in which sorbitol yield remained at 98% after 4 cycles with little or no metal agglomeration. The catalyst was applied to glucose solutions as high as 20 wt% with 97% sorbitol yields being obtained at 140 ℃ in 20 h. The developed bimetallic porous carbon sphere catalysts take advantage of sustainably-derived materials in their structure and are applicable to related biomass conversion reactions.