Unlocking the Potential of Oxide‐Based Catalysts for CO<sub>2</sub> Photo‐Hydrogenation: Oxygen Vacancies Promoted C─O Bond Cleavage in Key Intermediates
Zhexing Lin, Zhengwei Yang, Jiajia Wang, Jun Wang, Huiting Huang, Jianyong Feng, Huihui Yan, Minyue Zhao, Xinyi Liu, Wangxi Liu, Zhaosheng Li, Zhigang Zou
Abstract
Abstract Oxygen vacancies are generally recognized to play significant roles in CO 2 adsorption and activation during CO 2 hydrogenation. However, by revisiting its structural/electronic affinity for a range of oxygen‐containing intermediates in CO 2 hydrogenation processes, the additional roles of oxygen vacancies can be long overlooked and underestimated. Herein, using CO 2 (photo‐)methanation as a model reaction, Co 3 O 4 with abundant oxygen vacancies is employed to investigate the relationship between oxygen vacancies and the formation/conversion of oxygen‐containing intermediates. Combined analyses of in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations reveal that the key intermediate is formate, whose C─O bond cleavage is inferred to be the rate‐limiting step during CO 2 methanation on Co 3 O 4 . Remarkably, leveraging the oxygen vacancy‐mediated C─O bond scission to accelerate the conversion of formate, the CH 4 production activity (1108.1 mmol g −1 h −1 ) and selectivity (93%) are improved significantly. This comprehensive study provides valuable insights into the multifaceted roles of oxygen vacancies in CO 2 hydrogenation reactions, establishing a solid foundation toward the design and development of high‐performance oxide‐containing/‐based catalysts for the conversion of CO 2 into various valuable chemicals.