Donor−acceptor catalysis with defective MoS2 and Fe0 breaks barriers to perchlorate reduction under mild conditions

Perchlorate (ClO 4 − ) contamination in water poses global health risks, yet its efficient reduction to harmless Cl − under mild conditions remains challenging. Here, we report a donor−acceptor catalytic system comprising defective MoS 2 on N-doped carbon (MoS 2 −NC) coupled with zerovalent iron (Fe 0 ), which enables rapid ClO 4 − reduction at near-neutral pH (rate constant, 2.36 h −1 ), yielding Cl − as the sole product. In the MoS 2 −NC/Fe 0 system, Fe 0 acts as the electron donor, while undercoordinated Mo atoms in defective MoS 2 serve as the active sites, and N-doped carbon mediates electron transfer and optimizes the electronic environment for ClO 4 − reduction. The reduction proceeds via oxygen atom transfer, involving Cl−O bond cleavage, O binding to Mo sites, and hydrodeoxygenation of the Mo-bound O atoms. Our observations offer a practical strategy for ClO 4 − reduction without harsh conditions or noble metals and underscore the promise of donor−acceptor-based, defect-engineered catalysts for reductive transformation of challenging oxyanions.