Fast and Long‐Lasting Iron(III) Reduction by Boron Toward Green and Accelerated Fenton Chemistry

Abstract Generation of hydroxyl radicals in the Fenton system (Fe II /H 2 O 2 ) is seriously limited by the sluggish kinetics of Fe III reduction and fast Fe III precipitation. Here, boron crystals (C‐Boron) remarkably accelerate the Fe III /Fe II circulation in Fenton‐like systems (C‐Boron/Fe III /H 2 O 2 ) to produce a myriad of hydroxyl radicals with excellent efficiencies in oxidative degradation of various pollutants. The surface B−B bonds and interfacial suboxide boron in the surface B 12 icosahedra are the active sites to donate electrons to promote fast Fe III reduction to Fe II and further enhance hydroxyl radical production via Fenton chemistry. The C‐Boron/Fe III /H 2 O 2 system outperforms the benchmark Fenton (Fe II /H 2 O 2 ) and Fe III ‐based sulfate radical systems. The reactivity and stability of crystalline boron is much higher than the popular molecular reducing agents, nanocarbons, and other metal/metal‐free nanomaterials.