Modulating the electronic structure of Ni-Co alloy catalysts enhances corn stalk lignin hydrodeoxygenation into phenolic monomers

The production of phenolic monomers from agricultural waste biomass is environmentally friendly, economical, and sustainable. Here, we synthesized floral-like Ni-Co alloy catalysts via hydrothermal method for hydrodeoxygenation (HDO) of corn stalk lignin (CSL) to phenolic monomers. The optimized Ni1Co2Al-LDO-500 catalyst exhibits excellent catalytic performance for HDO of CSL, with lignin oil and phenolic monomer yields as high as 63.37 wt% and 46.63 wt% at 240 °C, respectively. XRD and TEM characterization confirms the formation of Ni-Co alloys, and XPS analysis reveals that the electron transfer between Ni and Co in the catalysts enhances the efficient activation of H2 and the hydrogenation breaking of C-O bonds. Moreover, the possible reaction pathways and reaction mechanisms of β-O-4 bonds hydrogen cleavage reaction over NiCoAl-LDO catalysts were elucidated by combining model reaction and 2D HSQC NMR analyses. Understanding the synergistic effect of Ni-Co alloy and acid site in NiCoAl-LDO catalysts in the HDO of CSL facilitates the efficient depolymerization of lignin for the production of phenolic products.