Enhancement of H2O2 decomposition efficiency by the co-catalytic effect of iron phosphide on the Fenton reaction for the degradation of methylene blue

The greatest problem in the homogeneous Fenton reaction is the low production of HO center dot owing to the slow Fe-III/Fe-II cycle. In this study, we demonstrate a new co-catalyst of FeP and trace Fe2+ that can greatly enhance the decomposition efficiency of H2O2 and accelerate the degradation of methylene blue (MB). This co-catalyst is applicable in a broad pH range (pH = 3.0 -9.0) and capable of degrading 95.74% and 89.01% of MB with 100 ppm in concentration within 30 s at pH 3 and 5, and 99.65% and 90.06% within 3 min at pH 7 and 9. The coexistence of FeP with Fe-II accelerates the Fe-III/Fe-II cycle by electron transfer between Fe delta+ in FeP and Fe-III. Mossbauer spectra and density functional theory calculations indicate that the unique structure of FeP plays an important role in accelerating the Fe-III/Fe-II cycle.