Metal free benzothiadiazole-diketopyrrolopyrrole-based conjugated polymer/g-C3N4 photocatalyst for enhanced sterilization and degradation in visible to near-infrared region.

In recent years, photocatalytic technology has attracted wide attention in environmental treatment, exploring non-toxic and metal-free photocatalysts is imminent to meet sustainable development. However, semiconductors with wide spectral response are rarely studied and applied in the field of photocatalysis. Herein, a new narrow band-gap polymer PFBDT-DPP (P3) with wide absorption from 500 to 860 nm was synthesized and further constructed heterostructure with g-C3N4 for photocatalytic sterilization and degradation of organic pollutant Rhodamine B (RhB). The optimal antibacterial rate for Escherichia coli reached 99.8% after 190 min of light irradiation and for Staphylococcus aureus reached 96.8% after 120 min of irradiation, and the highest degradation efficiency of RhB by P3/g-C3N4 was 98.9% within 60 min light irradiation, while g-C3N4 displayed an unsatisfactory sterilization and photodegradation performance. This is mainly attributed to the broadened light absorption range and enhanced carrier separation efficiency of P3/g-C3N4. This work could provide a new strategy to fabricate metal-free photocatalysts with high utilization of sunlight and excellent photocatalytic performance.