Tuning the Reduction Degree of Ni-Based Catalysts for Selective Hydrogenation of Furfural

The selective hydrogenation of biomass-derived compounds is pivotal for the synthesis of high-value-added chemicals. In this study, Ni2Al-LDO（layered double oxide） metal oxide catalyst featuring highly dispersed surface NiO was synthesized via a structural topological transformation using layered double hydroxides. The catalyst exhibited excellent performance in the hydrogenation of furfural, achieving 91.42% yield of furfuryl alcohol (FOL) at 160 °C and 1.4 MPa H2. Gradual reduction of Ni2Al-LDO produced Ni/NiO mixtures, enabling tunable shift from FOL to tetrahydrofurfuryl alcohol (HFOL) as the NiO content decreased and the Ni content increased. After a two-hour reduction at 700 °C, the HFOL yield reached 93.95%. CO2-TPD, NH3-TPD, and FT-IR measurements revealed that variations in reduction degree on nickel influenced the adsorption behavior of furfural. NiO species could only adsorb the C=O group of furfural, whereas the flat adsorption mode on the metallic Ni surface facilitated the simultaneous adsorption and activation of both the furan ring and the carbonyl group of furfural.