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 m(2) 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.