Air-stable and reusable nickel phosphide nanoalloy catalyst for the highly selective hydrogenation of D-glucose to D-sorbitol
S. Yamaguchi, S. Fujita, K. Nakajima, S. Yamazoe, J. Yamasaki, T. Mizugaki, T. Mitsudome
Green Chemistry, accepted.

The hydrogenation of carbohydrates to polyols is an industrially important process but has the significant drawbacks of using air-unstable non-noble metal catalysts with low activity, and requirement of harsh reaction conditions. Herein, we report that a hydrotalcite (HT)-supported nickel phosphide nanoalloy (nano-Ni2P/HT) exhibits both air stability and high activity for the selective hydrogenation of D-glucose to D-sorbitol in water. The nano-Ni2P/HT catalyst shows excellent activity to provide D-sorbitol in excellent yield with >99% selectivity under mild reaction conditions. Typically, nano-Ni2P/HT is the first non-noble metal catalyst for operating under just 1 bar of H2 or ambient temperature. This high performance of nano-Ni2P/HT is significantly different from conventional Ni(0) and NiO nanoparticles, and Raney catalysts, which result in almost no production of D-sorbitol, demonstrating the unique catalysis of nano-Ni2P/HT. Furthermore, nano-Ni2P/HT shows the highest activity among those reported for non-noble metal catalysts. The nano-Ni2P/HT catalyst can be also reused while retaining its high activity and selectivity, and the successful transformation of a concentrated D-glucose solution (50 wt%) has been achieved. This is the first example of an air-stable, highly active, and reusable non-noble metal catalyst that can replace conventional catalysts, thus paving the way for the cheap, green, and sustainable production of D-sorbitol.