The Interplay between Structure and Product Selectivity of CO2 Hydrogenation. Issue 33 (28th June 2019)

• Record Type: Journal Article
• Authors: Yang, Chengsheng; Liu, Sihang; Wang, Yanan; Song, Jimin; Wang, Guishuo; Wang, Shuai; Zhao, Zhi‐Jian; Mu, Rentao; Gong, Jinlong
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 33(2019)
• Page Start: 11242
• Page End: 11247
• Publication Date: 2019-06-28
• Subjects: CO2 hydrogenation -- Co3O4 -- crystallographic surfaces -- methoxy -- reducibility; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201904649
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Identification of the active structure under reaction conditions is of great importance for the rational design of heterogeneous catalysts. However, this is often hampered by their structural complexity. The interplay between the surface structure of Co3 O4 and the CO2 hydrogenation is described. Co3 O4 with morphology‐dependent crystallographic surfaces presents different reducibility and formation energy of oxygen vacancies, thus resulting in distinct steady‐state composition and product selectivity. Co3 O4 ‐0 h rhombic dodecahedra were completely reduced to Co 0 and CoO, which presents circa 85 % CH4 selectivity. In contrast, Co3 O4 ‐2 h nanorods were partially reduced to CoO, which exhibits a circa 95 % CO selectivity. The crucial role of the Co3 O4 structure in determining the catalytic performance for higher alcohol synthesis over CuCo‐based catalysts is demonstrated. As expected, Cu/Co3 O4 ‐2 h shows nine‐fold higher ethanol yield than Cu/Co3 O4 ‐0 h owing to the inhibition for methanation. Abstract : The correlation of Co3 O4 catalysts having different crystallographic surfaces with reducibility and the formation energy of oxygen vacancies is described. Distinct product selectivity of CO2 hydrogenation is observed. The key step (CH3 −O* bond breaking), which affects C1 product distribution, was identified by in situ DRIFTS and DFT, suggesting that oxygen vacancies can promote the CH3 −O* bond breaking.