On-Demand, Highly Tunable, and Selective 5-Hydroxymethylfurfural Hydrogenation to Furan Diols Enabled by Ni and Ni3Ga Alloy Catalysts

Catalytic conversion of the biobased platform chemical 5-hydroxymethylfurfural (HMF) into high-value-added products (e.g., diols) has attracted considerable attention, where controlling the products' selectivity is a crucial and challenging issue. Herein, a series of hydrotalcite-based Ni and Ni3Ga alloy catalysts were prepared for HMF hydrogenation into furan diols. By optimizing the loaded metal and reduction temperature, >99% BHMTHF and 95.6% BHMF yields were gained over Ni1.5Al-LDO-700 and Ni1.5GaAl-LDO-700, respectively, under mild conditions. Characterizations and DFT calculations showed that the doped Ga resulted in charge transfer from Ga to Ni and disrupted the Ni arrangement, which weakened the furan ring adsorption and favored its tilted adsorption on the Ni3Ga alloy, consequently inhibited deep hydrogenation, and selectively produced BHMF. These catalysts were also versatile for hydrogenation of other furan aldehydes, achieving high selectivity toward un-/saturated alcohols on demand. This study provides an advanced strategy for the rational design of superior catalysts for tuning product selectivity on demand, with practical potential for upgrading biomass-derived platform molecules.