Highly effective removal of BPA with boron-doped graphene shell wrapped FeS2 nanoparticles in electro-Fenton process: Performance and mechanism

To prevent metal catalysts from agglomeration and leaching, encapsulating metal nanoparticles in carbon shells has attracted much attention in electro-Fenton (EF) processes. However, most of the carbon?metal catalysts were suffering from slow regeneration of Fe2+ due to the unavailable redox reactions at electrode surface, which hindered the EF efficiency. Here, we report a novel boron doped graphene (BrGO) wrapped FeS2 nanocomposite (FeS2@BrGO), which exhibits extremely high catalytic performance due to the synthetic interaction between BrGO and FeS2, as well as the efficient regeneration of Fe(II). The EF system with FeS2@BrGO could completely remove 50 mg L-1 bisphenol A within 20 min under neutral pH. EPR results suggest the existing of abundant persistent free radicals and reductive sulfur could directly donate electron to Fe(III). The electrochemical measurements further demonstrated the decreased reduction potential of Fe(III)/Fe(II) by the coordination between Fe(III) and surface oxygen-containing functional groups. Reactive organic radicals also played an important role in reducing Fe(III) to Fe(II). These findings provide a new strategy for hybrid catalysts combining graphene shells with metal sulfide, which has great potential in wastewater treatment.

Automated summary

The novel boron doped graphene wrapped FeS2 nanocomposite exhibited high catalytic performance in removing bisphenol A, with efficient regeneration of Fe(II). The interaction between graphene shells and metal sulfide played a crucial role in enhancing the efficiency of the catalyst.