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 CO 2 reduction. Herein, Co 3 O 4 /ZrO 2 mesoporous octahedrons are synthesized through facile pyrolysis of UIO-66@ZIF-67 core/shell octahedrons. The as-obtained Co 3 O 4 /ZrO 2 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 CO 2 adsorption are successfully enhanced. In addition, density functional theory calculations reveal that ZrO 2 tailors the reaction pathway of CO 2 reduction by promoting CO 2 activation to *CO 2 and intermediate formation (*COOH and *CO), as well as decreasing the energy barrier of the rate-limiting step (*CO→CO). Thus, the Co 3 O 4 /ZrO 2 mesoporous octahedrons afford a turnover frequency of 28.82 h −1 , 16.95-fold larger than pure Co 3 O 4 .