Mechanistic analysis identifying reaction pathways for rapid reductive photodebromination of polybrominated diphenyl ethers using BiVO4/BiOBr/Pd heterojunction nanocomposite photocatalyst

Polybrominated diphenyl ethers (PBDEs), previously incorporated in a wide variety of common products, can now be found throughout the environment. Because of their environmental persistence and the potential health hazards they pose to humans and wildlife, they have been added to the Stockholm Convention on Persistent Organic Pollutants, and they continue to be of significant concern. We report herein the first application of a nanocomposite catalyst consisting of a m-BiVO4/BiOBr heterojunction surface-decorated with Pd nanoparticles in the photocatalytic reductive debromination of PBDEs using visible light. Specifically, this system demonstrated both rapid and complete debromination of 2,2 ',4,4 '-tetrabromodiphenyl ether (BDE-47), with an exceedingly large initial pseudo-first-order rate constant of 1.33 min(-1). Analysis of the reaction mechanism identified the stepwise degradation pathway to generate the final diphenyl ether product as well as the role of the alcohol-based sacrificial reagent. Such information provides routes towards new approaches for environmental remediation by identifying reaction pathways for common organic pollutants that remain challenging to degrade via sustainable methods.

Automated summary

In this study, a nanocomposite catalyst consisting of a m-BiVO4/BiOBr heterojunction surface-decorated with Pd nanoparticles was used for the photocatalytic reductive debromination of PBDEs using visible light. The catalyst showed rapid and complete debromination of BDE-47 with a high reaction rate constant. These findings provide new insights into the degradation of common organic pollutants via sustainable methods.