3D structure-functional design of a biomass-derived photocatalyst for antimicrobial efficacy and chemical degradation under ambient conditions.

Surface sterilization and hazardous chemical degradation under ambient conditions can provide significant benefits for public and environmental health. Materials with sterilization and chemical degradation capacity under sunlight can efficiently reduce infectious disease incidence rates and toxic chemical exposure. Utilizing renewable energy for sustainable sterilization and degradation is more desirable as it reduces the potential secondary contamination. Herein, we report functional structure design using lignin, a renewable carbon heterogeneous polymer, to synthesize a highly efficient and stable photocatalyst that degrades environmentally hazardous organic compounds rapidly. Through a hydrolysis reaction between Ti-OH and the hydroxyl groups of lignin, Ti-O-C and Ti-O-Ti bonds were established and a lignin based photocatalyst with a hollow sphere structure (C_lignin@H-TiO₂) was formed. The presence of a homozygous carbon modified TiO₂ structure contributes to the enhanced photodegradation activity with solar light. The close hetero-interfacial contact between carbonized lignin and TiO₂ further improves the photocatalytic efficiency by facilitating effective charge carrier separation. After synthesis optimization, the resulting C_lignin@H-TiO₂ photocatalyst exhibits excellent performance in the degradation of atenolol under solar light irradiation with 100% degradation within five minutes. Additionally, it efficiently removes approximately 50% of PFOA and kills about 90% of bacteria within three hours. The uniform distribution of lignin within the crosslinking structures ensures a durable carbon modified TiO₂ framework, which remains stable after 10 cycles of usage. The robustness of the lignin-based photocatalyst enables incorporating the catalyst into diversified material formats and various usages. Coating of the photocatalyst onto device surfaces shows bacterial killing efficacy under sunlight. The photocatalysts based on lignin valorization present a green chemistry approach for environmental remediation and surface sterilization, which has long-term environmental protection benefits, with broad applications in toxin treatment and health protection against pathogen infection.