Transition metal catalysts are known to activate persulfate, but the properties that govern the intrinsic activity of these catalysts are still unknown. Here, we developed a series of catalysts with transition metals anchored on carbon nanotubes (denoted M–N–CNTs, where M = Co, Fe, Mn, or Ni) containing single-atom M–N moieties, to activate peroxymonosulfate for the efficient nonradical oxidation of sulfamethoxazole. The spin state of M–N–CNTs strongly determined their catalytic activity. A large effective magnetic moment with a high spin state (e.g., Co–N) favored the overlap of d orbitals with oxygen-containing adsorbates (such as peroxo species) on metal active sites and promoted electron transfer, which facilitated peroxymonosulfate adsorption and enhanced the oxidation capacity of the reactive species. These findings advance the mechanistic understanding of transition metal-mediated persulfate activation and inform the development of efficient spintronic catalysts for environmental applications.

This work reports on the preparation of a noble-metal-free and highly active catalyst that proved to be an efficient and green reductant with renewable capacity. Nitridation of a silent Ta1.1O1.05 substrate led to the formation of a series of TaOxNy hollow nanocrystals that exhibited outstanding activity toward catalytic reduction of nitrobenzenes under ambient conditions. ESR and XPS results indicated that defective nitrogen species and oxygen vacancies at the surfaces of the TaOxNy nanocrystals may play synergetic roles in the reduction of nitrobenzenes. The underlying mechanism is completely different from those previously reported for metallic nanoparticles. This work may provide new possibilities for the development of novel defect-meditated catalytic systems and offer a strategy for tuning any catalysts from silent to highly reactive by carefully tailoring the chemical composition and surface defect chemistry.

A novel photocatalytic system for highly efficient non-oxidative coupling of methane was demonstrated by dispersing a metal loaded TiO₂ catalyst on the light-diffuse-reflection surface with a continuous flow reactor.

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