Reinventing Fenton Chemistry: Iron Oxychloride Nanosheet for pH-Insensitive H₂O₂ Activation

This study intends to reinvent classical Fenton chemistry by enabling the Fe­(II)/Fe­(III) redox cycle to occur on a newly developed FeOCl nanosheet catalyst for facile hydroxyl radical (^•OH) generation from H₂O₂ activation. This approach overcomes challenges such as low operating pH and large sludge production that have prevented a wider use of otherwise attractive Fenton chemistry for practical water treatment, in particular, for the destruction of recalcitrant pollutants through nonselective oxidation by ^•OH. We demonstrate that FeOCl catalysts exhibit the highest performance reported in the literature for ^•OH production and organic pollutant destruction over a wide pH range. We further elucidate the mechanism of rapid conversion between Fe­(III) and Fe­(II) in FeOCl crystals based on extensive characterizations. Given the low-cost raw material and simple synthesis and regeneration, FeOCl catalysts represent a critical advance toward application of iron-based advanced oxidation in real practice