Keywords: biochar; carbon-encapsulated; MSF@Lignin; overall water splitting
Common precursors for carbon materials typically include petroleum-based polymers or MOF materials. However, these materials often encounter challenges such as metal aggregation, high cost, and metals leaching. In this work, a novel of approach lignin-metal supramolecular framework complex (MSF@Lignin) is introduced. These complexes are formed through oxidative ammonolysis of lignin (OAL) to synthesize a nitrogen-doped carbon-encapsulated CoRu nanocatalyst (CoRu@OALC) via in situ carbonization. CoRu@OALC exhibited exceptional performance in both HER (90 mV) and OER (200 mV) at the current density of 10 mA cm−2, with an overall water splitting voltage of 1.5 V and outstanding stability under high density. During the pyrolysis process, metal became encapsulated by lignin-derived carbon, occurring within the temperature range of 600–700 °C. In the catalytic process, active sites are primarily located within the defects in lignin-derived carbon, showcasing a unique “self-healing” phenomenon within the carbon layer. Oxygen-containing intermediates (*OH, *O, and *OOH) facilitated the reconstruction of defects on the carbon layer, while the hydrogen-containing intermediates (*H) contributed to the reappearance of a defect-rich structure.
