Achieving satisfactory organic transformation reactions under mild conditions using high-performance catalysts that are composed of cost-effective and earth-abundant elements has always been an aspiration for scientists in the field of catalysis. In this work, CoMn2O4 microspheres with intriguing porous yolk-shell architecture have been constructed by a facile solvothermal reaction and post-calcination treatment, and were employed for the first time in the epoxidation reaction of styrene (SER). Among the series of CoMn2O4 catalysts, the one calcined at 600 °C (CMO-600) displays superior catalytic performance in the SER, achieving an excellent conversion of 97.7%, a prominent selectivity of 83.7% to SO and a good recycling performance. The remarkable SER performance of the CMO-600 benefits from the collaborative influences derived from the unique porous yolk-shell architecture and the synergy of the two metal centers regarding high surface Mn2+/ Mn3+ atomic ratio, abundant redox couples and rich oxygen vacancies. The reaction pathway analysis and the activation energy measurement were performed as well to unravel the inner relationship between the catalytic behavior and the catalyst properties. This study affords a fresh impetus to the developing of high-performance bimetallic oxides for oxidation reactions in organic catalysis.
Keywords: Bimetallic; CoMn(2)O(4); Epoxidation; Styrene; Synergistic effect.
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