Tailored ozone activation on geometrical-site-dependent cobalt with selective coordination.

Cobalt-containing spinel oxides are promising platforms to fine-tune the intrinsic activity/selectivity of their geometric sites in catalysis. However, the role of tetrahedrally occupied Co (Co) and Co in an octahedral site (Co) in controlling the catalytic activity remains controversial. Herein, we investigated a geometrical-site-dependent catalytic activation of ozone respectively on the Co and Co sites. The same exposure of [111] crystal facet is achieved by substituting those undesired sites with catalytically inactive cations. The highly spin-polarized Co sites invoke strong orbital interactions and intensive electron transfer with the adsorbed O and become the active sites for selectively producing surface-bound hydroxyl radicals (OH) and avoiding the formation of unfavorable singlet oxygen (O), resulting in a 17.6-fold increase in turnover frequency (TOF). This work enlightens the spin-polarized electronic states into regulating the reaction thermodynamics in transition metal oxide-induced catalysis and envisages the practical application potentials of geometric site engineered spinel oxides.