Graphene and Carbon Nitride‐Based Catalysts Activating Persulfates Towards Oxidation of Benzyl Alcohol and Depolymerisation of Lignin Dimer

The structure–activity relationship between persulfate activation by carbon‐based catalysts and organic compound oxidation is a key scientific issue. However, previous studies have paid insufficient attention to this topic. This article systematically elucidates this relationship and mechanism of action using modified carbon catalysts. Using selective oxidation of benzyl alcohol to benzaldehyde and lignin dimer depolymerisation as reaction models, nitrogen‐doped graphene (NG‐4) and CoFe ₂ O ₄ /g‐C ₃ N ₄ (30‐CFO/BCN) composites were systematically characterised by XRD, XPS, EPR, and other techniques. In benzyl alcohol oxidation, NG‐4 achieves 99.2% benzaldehyde selectivity via an electron‐transfer‐dominated non‐radical pathway. Its performance is attributed to the synergistic interaction between pyridine nitrogen and ketone carbonyl, driving both radical and non‐radical pathways. In lignin depolymerisation, 30‐CFO/BCN composite catalyst activates persulfate to generate SO ₄ • ⁻ ‐dominated radicals, achieving complete dimer conversion with 70.8% veratraldehyde yield. This enhanced activity is closely related to the increased Co ²⁺ /Co ³⁺ ratio and oxygen vacancy concentration. Furthermore, incorporating this catalyst into functional hydrogel systems expands its application potential in conductive materials and wastewater treatment. This study provides fundamental insights into the reaction mechanisms of persulfate‐based catalytic systems and offers theoretical guidance for catalyst design in green synthesis and biomass resource utilisation.