Molecular and kinetic insights to boron boosted Fenton-like activation of peroxymonosulfate for water decontamination

In this work, crystalline boron is applied as a green co-catalyst to accelerate the redox processes in the Fe(III)/PMS(peroxymonosulfate) system. The semi-metallic B-B bonds in the icosahedra B12 unit of boron will donate electrons to reduce Fe(III) to initiate Fenton-like PMS activation to generate hydroxyl radical (•OH), sulfate radical (SO4•−) and high-valence Fe(IV). Meanwhile, surface boron can directly cleave the peroxide O-O bonds of PMS molecules to produce •OH. The contributions of radical and Fe(IV) can be regulated by Fe(III) dosage, and parallel radical and nonradical oxidation will enable non-selective degradation of diverse organic contaminants with high PMS utilization efficiency. Moreover, Fe(III) accelerates the self-clean of boron surface and secures continuous exposure of active sites. Spontaneously, boron experiences stepwise oxidation and hydrolysis into soluble products without generating toxins. The novel Boron/Fe(III)/PMS system overcomes the rate-limiting step in Fenton chemistry and realizes exceptional efficiency and stability in long-term operations.