Preparation and properties of lignin-based carbon/ZnO photocatalytic materials

Lignin-based carbon/zinc oxide (LCZ) composites with excellent porous structures were prepared by a one-step carbonization method using lignin as the carbon source. The effects of different carbonization conditoions (temperature, carbonization time and QAL addition) on the pore structure of the composites were investigated. The results showed that the obtained LCZ composite had the largest specific surface area (317.765 m2 g−1) and pore volume (0.4344 mL g−1) when the QAL addition was 4 g and carbonization at 600 °C for 2 h (LCZ-600-2-4). This porous structure enables a tighter bond between the lignin-based carbon and ZnO. The photodegradation performance of the prepared LCZ under simulated solar light (500 W Xe lamp) irradiation was improved for the rapid transfer of photogenerated electrons. Compared with pure ZnO, the degradation rate of LCZ reached 92% and 91% of methyl orange (MO) and rhodamine B (Rh B) in 2 h. LCZ was tested for material stability, and it showed good acid–base stability and the degradation rate of RhB kept above 80% after five cycles. This simple and scalable method opens up a green pathway for the preparation of photoelectric conversion materials.