Spin state-tailored tetrahedral and octahedral cobalt centers on millimetric Co-Al oxide catalysts as dual sites for synergistic peroxymonosulfate activation

Rationally developing millimetric metal catalysts with tailored electron function is crucial for water decontamination, but challenges remain due to insufficient understanding on their electronic structure engineering and the underlying mechanism. Here, through constructing bonded Co-O-Al unit sites on the millimetric gamma-Al2O3 spheres, we report a feasible and scalable strategy of modulating the 3d electron configurations and spin states of supported tetrahedral and octahedral cobalt cations just by adjusting the radius of support curvature. The tetrahedral and octahedral cobalt centers with tailored electron spin states showed a synergism in peroxymonosulfate activation to generate SO4 center dot- and reactive oxygen (O*), in which the latter was converted into 1O2 and O2 center dot-. The electronic structure-oriented spin catalysis affected the formation of reactive species and the pathway of pollutant degradation. This work will stimulate the design and mass production of macroscopic spin catalysts with superior activity, reusability and stability for catalytic water purification.