Lignin to Monoaromatics with a Carbon-Nanofiber-Supported Ni–CeO2–x Catalyst 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–CeO2–x supported on carbon nanofibers. In situ H2 production 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.