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

Abstract

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.