Construction of Ni−Re Supported on Hydrotalcite-Derived MgAl Catalysts for Promoting the Ring Hydrogenation of Furfural into Tetrahydrofurfuryl Alcohol in Water

Abstract

Biomass-derived feedstocks play a vital role in sustainable economies for renewable energy, waste management, energy security, and commercial prospects. This study focused on promoting the ring hydrogenation of furfural (FAL) into tetrahydrofurfuryl alcohol (THFA) in an aqueous solution using a potential Ni−Re-supported hydrotalcite-derived MgAl catalyst at different Ni : Re molar ratios. Structural analyses, such as an in situ time-resolved X-ray absorption near edge structure, under H2 reduction elucidated the simultaneous transformation of Re6+ and Re7+ to Re0 with the remaining highly stable Ni2+. The construction of Ni−Re on hydrotalcite-derived MgAl catalyst resulted in the alleviated H2 reduction behavior, facilitated H2 adsorption and desorption processes, and suitable catalyst acidity detected by H2 temperature-programmed reduction, and H2 and NH3 temperature-programmed desorption experiments, respectively. Under optimized conditions, a maximum THFA yield of 78 % with a complete FAL conversion was attained using Ni1Re0.16/MgO−Al2O3 catalyst at a reaction temperature of 140 °C, H2 pressure of 20 bar, catalyst loading of 20 %, and reaction time of 2 h in a H2O system. Isotopic deuterium (D2O) labeling revealed that D substitution was notably pronounced through isotopic exchange between the D atom from D2O and H atom in FAL during its hydrogenation to THFA.