MOF-derived Co₃O₄/ZrO₂ mesoporous octahedrons with optimized charge transfer and intermediate conversion for efficient CO₂ photoreduction

Regulating charge transfer and reaction pathways are effective strategies for boosting photocatalytic CO₂ reduction. Herein, Co₃O₄/ZrO₂ mesoporous octahedrons are synthesized through facile pyrolysis of UIO-66@ZIF-67 core/shell octahedrons. The as-obtained Co₃O₄/ZrO₂ mesoporous octahedrons are assembled by highly dispersive and small-sized nanoparticles, with 13 nm average particle size and 5.8 nm pore width, leading to a high specific surface area of 43.11 m² g⁻¹. Benefiting from active-site engineering, the charge-transfer kinetics and CO₂ adsorption are successfully enhanced. In addition, density functional theory calculations reveal that ZrO₂ tailors the reaction pathway of CO₂ reduction by promoting CO₂ activation to *CO₂ and intermediate formation (*COOH and *CO), as well as decreasing the energy barrier of the rate-limiting step (*CO→CO). Thus, the Co₃O₄/ZrO₂ mesoporous octahedrons afford a turnover frequency of 28.82 h⁻¹, 16.95-fold larger than pure Co₃O₄.