Novel non-precious metal loading Multi-metal oxide Catalysts for Lignin Depolymerization

In this work, a low-cost silicon-based multi-metal oxide sphere (glass bead, GB) and its derivatives were used as novel catalysts to depolymerize poplar lignin. The surface morphology (flaky structure) and specific surface area of GB could be effectively changed by the subcritical water treatment. The treated GBs were further loaded with nonprecious metals (Ni and Mn) to obtain GB derivatives. Based on the results of product analysis, it was found that the introduction of nonprecious metals could effectively prevent the departure of the methoxy group from the aromatic hydrocarbon structure, thus reducing lignin polycondensation (Ni: 8.8 wt % solid residue and 3.5 wt % char, Mn: 5.1 wt % solid residue and 1.7 wt % char) and increasing the yield of monomer products (Ni: 13.4 wt %, Mn: 15.5 wt %). Furthermore, GB derivatives could be recycled to catalyze depolymerization of lignin, and the monomeric product yield remained above 12 wt %.