Construction of Multistep 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 multistep charge transfer pathways with photothermal-driven reactions to improve photoconversion efficiency. By incorporating Bi⁰/Bi³⁺ metal as an electron transport mediator for multistep 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 photoconversion rates of PP into CO by Bi⁰@Bi³⁺-KNbO₃ reached 209.41 µmol g_cat⁻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 g_cat⁻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.