Lignin to Monoaromatics with a Carbon-Nanofiber-Supported Ni-CeO_2-xCatalyst Synthesized in a One-Pot Hydrothermal Process

The synthesis of effective heterogeneous catalysts is one of the main challenges toward hydrothermal processing of wood-derived biomass into marketable sustainable chemicals. Many of these catalysts are based on noble metals and are normally synthesized using multiple steps in time-consuming processes. Here, we have developed a one-pot catalyst synthesis method for Ni-CeO_2-xsupported on carbon nanofibers.In situH₂production through formic acid decomposition enabled the synthesis of catalysts in their reduced form, with ceria as Ce³⁺and presence of metallic Ni. This catalyst promoted Kraft lignin conversion in supercritical water at short reaction times with a 79 wt % yield of a bio-oil composed of nearly 69 wt % of monoaromatics. Thus, lignin breakdown was achieved without resourcing to noble metal catalysts, molecular H₂, or cosolvents, with a decrease in catalyst synthesis time and unit operations and with an attractive yield of a chemically uniform product fraction.