Advanced boron-doped diamond-metal oxide heterojunctions for electrochemical degradation of PFOS: Tackling 'Forever Chemicals' in real water matrices

In this study, boron-doped diamond-metal oxide heterojunctions were investigated as anodes for the electrochemical removal of perfluorooctane sulfonate (PFOS), a persistent environmental pollutant. The results demonstrate that the incorporation of metal oxides such as WO3 and V2O5 significantly influences the removal efficiency of PFOS. The WO3/BDD heterojunction demonstrated superior performance, achieving higher PFOS removal rates than the V2O5/BDD system. The V2O5 thin layer was unstable and leached from the BDD surface during electrolysis. In contrast, the WO3 thin layer remained stable under identical conditions and acted as an effective catalytic interface, enhancing PFOS degradation efficiency. These findings highlight the potential of boron-doped diamond-metal oxide heterojunctions, particularly WO3/BDD, as promising solutions for the remediation of PFOS-contaminated environments. Atomistic simulations show that for WO3, the most adsorptive surface was the 1 x 1 configuration (48 & Aring;2) with PFOS in the ontop orientation, exhibiting an adsorption energy of-1.74 eV. Moreover, it was predicted that PFOS partially decomposes and the-OH group forms a covalent bond with tungsten atoms on the surface, which increases the adsorption affinity. This indicates the possibility of chemisorption of PFOS on WO3, which may increase the efficiency of the removal process.