Fe2O3@FeB composites facilitate heterogeneous Fenton process by efficient Fe(III)/Fe(II) cycle and in-situ H2O2 generation

In this study, we fabricated a micro-nano structured Fe2O3@FeB composites by treating commercial Fe2O3 with sodium borohydride. The outside amorphous FeB alloy shell endowed the Fe2O3@FeB with remarkable Fenton-like performance in organic pollutants oxidation by efficient Fe(III)/Fe(II) cycle. For instance, the pseudo first-order rate constants of RhB degradation using Fe2O3@FeB as Fenton reagent was 74.6 times that of the Fe2O3 counterpart, the hydroxyl radical generation rate of Fe2O3@FeB was 1-3 orders of magnitude larger than that of other heterogeneous Fenton reagent. Further mechanistic study unveiled that FeB was oxidized accompanying with Fe(0) and B(0) continuously donated electrons to Fe(III) to secure the efficient generation of surface Fe(II), which could generate additional H2O2 by consecutive single-electron molecular oxygen activation (O2→•O2−→H2O2), leading to enhance •OH production and Fenton-degradation toward typical pollutants. This study provides a facile route for efficient heterogeneous Fenton and strengthens the vital role of molecular oxygen activation on Fenton-like process.