Anion Vacancies Triggered Spin Polarization Enables Efficient Piezocatalysis for Water Cleanup

The conversion of aromatic organic pollutants into value-added chemical feedstocks is still suffering from sluggish carbon reduction kinetics with spin-forbidden transitions. Here, we report an anion vacancy-triggered spin polarization strategy to efficiently convert phenol into carbon monoxide (CO) with fast kinetics. The creating Se vacancies (V_se) stimulate the spin polarization of both Fe and Mo in Fe single atom modified MoSe₂ (Fe/MoSe₂), in which spin polarization can enhance the quantity of spin electrons and facilitate the transport of electrons that share the same spin direction with greater efficiency in charge separation. Batch experiments and theoretical calculations reveal that the unpaired spin electrons of Fe and Mo atoms not only accelerate the formation and immobilization of key intermediate *COOH, but also provide spin electrons for *COOH further cleavage with a lower reaction energy barrier. Moreover, profiting from the crucial bridging role of peroxydisulfate (PDS), phenol can be first oxidized to carbonate/CO₂ through PDS activation and then provide a sufficient carbon source for CO formation with favorable reaction kinetics. Impressively, the Fe/MoSe₂ piezocatalysis coupled with PDS exhibits 298.28 µmol·g^-1 CO production rate for phenol degradation with over 60 h durability.