Construction of Multi-step Charge Transfer Pathways in Bi0@Bi3+-KNbO3 for Significantly Accelerated Photoconversion of Waste Plastics

Abstract

Photoconversion of waste plastics into valuable CO and CH3COOH represents a ground-breaking strategy for addressing plastic pollution issues. However, this process currently encounters significant challenges, primarily due to the limitation of catalyst activity and the difficulty in breaking C–C bonds. Herein, we present a novel approach that integrates multi-step charge transfer pathways with photothermal-driven reactions to improve photoconversion efficiency. By incorporating Bi0/Bi3+ metal as an electron transport mediator for multi-step charge transfer, we markedly enhanced the separation and transport of photoelectrons, thereby accelerating the generation of active species. Meanwhile, the heat generated by the localized surface plasmon resonance effect of Bi0 drove the reactions related to the photoconversion of polypropylene. Subsequently, the photo-conversion rates of PP into CO by Bi0@Bi3+-KNbO3 reached 209.41 μmol gcat-1 h-1, which is 27.55 times higher than that achieved with KNbO3. Furthermore, the dual Bi-Nb sites effectively stabilize the key intermediate *COOH, thereby promoting the production of CH3COOH at a rate of 213.00 μmol gcat-1 h-1. This strategy of boosting photoconversion activity of PP into CO and CH3COOH offers an effective green solution to the serious issue of plastic pollution.