Ni-Based multifunctional catalysts derived from layered double hydroxides for the catalytic conversion of cellulose to polyols

Abstract

The catalytic conversion of biomass to high-value-added products has attracted wide attention, especially the efficient and selective conversion of cellulose to valuable chemicals and fuels. In this study, using Ni, Al and Ni, Zn, Al layered double hydroxides (LDHs) as precursors, mixed metal oxide catalysts Ni-MMO and NiZn-MMO were synthesized. In the process of catalyzing the conversion of cellulose to polyols, the reaction conditions were an H₂ pressure of 4 MPa, temperature of 240 °C for 2 h, and the NiZn-MMO catalyst, which could achieve 100% conversion rate and excellent cycling performance. The characterization and reaction results showed that the size of the Ni active metal particles in the synthesized Ni-MMO and NiZn-MMO catalysts was very small, at about 1–2 nm only. ZnO in the NiZn-MMO catalyst mainly plays an isomerization role, promoting the formation of more 1,2-PG, while the strong interaction between Ni and Zn inhibits the dissolution of the Ni metal in the hydrothermal reaction. On the other hand, Ni mainly plays the role of rapid hydrogenation to avoid coking, which constitutes a multi-functional synergistic catalytic process for the conversion of cellulose to polyols in high-temperature water. This study provides economical and efficient catalysts, which are of great significance in the effective conversion of biomass.