Synergizing carbon vacancies and built-in electric fields in covalent triazine frameworks for photocatalytic cleavage of lignin C–C bonds into value-added chemicals

Solar-driven catalysis presents an environmentally benign pathway for transforming complex lignin into high-value aromatic derivatives under ambient environments. Among various metal-free photocatalysts, covalent triazine frameworks (CTFs) have attracted attention because of their robust structural stability and tunable electronic properties. A built-in electric field, characterized by a unique “push–pull” effect, offers an effective strategy to activate CTFs and unlock enhanced catalytic performance. Herein, a built-in electric field was firstly introduced into CTFs by the one-step ball milling red phosphorus method, and their functions in the green and cleaner photocatalytic cracking of lignin C–C bonds were studied. This distinct electronic environment originates from electron-rich P centers embedded centrally, interacting synergistically against electron-deficient nitro functionalities localized along the peripheral edges. Consequently, this specific asymmetric configuration substantially broadens the absorption spectrum while profoundly accelerating spatial charge dissociation. Furthermore, the applied kinetic energy inherently triggered the formation of empty carbon sites. Propelled by the synergistic interplay between intense electrostatic forces and these surface structural defects, the targeted molecular fragmentation achieved remarkable specific yields: hitting 30.89% for benzoic acid, 75.19% regarding benzaldehyde, alongside a 68.67% generation of phenyl formate. This work provides a simple and low-energy, cleaner-production-oriented strategy for fabricating photocatalysts applicable to sustainable biomass valorization.