Withered magnolia-derived BCDs onto 3D flower-like Bi₂WO₆ for efficient photocatalytic TC degradation and CO₂ reduction

The biomass-derived carbon quantum dots (BCDs, explored from the withered magnolia blossom) modified Bi₂WO₆ (Bi₂WO₆/BCDs) was prepared and used to remove the water contaminants. The biomass-derived carbon quantum dots-modified Bi₂WO₆ was synthesized by the unique hydrothermal technology and dialyzed method, showing excellent photocatalytic degradation activity of tetracycline and CO₂ photoreduction performance. The Bi₂WO₆/BCDs showed a better tetracycline (TC) degradation efficiency than that of Bi₂WO₆ (49 %) under the visible light, when mass of BCDs was 15 μL. Additionally, photo-electrochemical measurements proved the separation efficiency of electron-holes of Bi₂WO₆ was enhanced, due to the great electron transmission ability and light absorption of BCDs. The mechanism experiment showed that ·O₂ ^- was the main activity specie in the TC photodegradation process. Meanwhile, the Bi₂WO₆/BCDs also showed higher CO₂ photoreduction performance to CO (18.2 μmol/g) under UV–vis light than the pure Bi₂WO₆. The CO₂ reduction mechanism also investigated by in-situ FTIR. The favorable photocatalytic performances make the waste biomass carbon act as a new resource of application to wastewater treatment and carbon recycling process.