Surface Reconstruction of Ultrathin Palladium Nanosheets during Electrocatalytic CO2 Reduction

• Published in: Angewandte Chemie International Edition Vol. 59; no. 48; pp. 21493 - 21498
• Main Authors: Zhao, Yong, Tan, Xin, Yang, Wanfeng, Jia, Chen, Chen, Xianjue, Ren, Wenhao, Smith, Sean C., Zhao, Chuan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 23.11.2020
• Edition: International ed. in English
• Subjects: Carbon dioxide; Carbon monoxide; Catalysts; Chemical reduction; CO2 reduction; electrocatalysis; Nanosheets; Nanostructure; Palladium; palladium nanosheet; Reconstruction; surface reconstruction
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202009616

A surface reconstructing phenomenon is discovered on a defect‐rich ultrathin Pd nanosheet catalyst for aqueous CO2 electroreduction. The pristine nanosheets with dominant (111) facet sites are transformed into crumpled sheet‐like structures prevalent in electrocatalytically active (100) sites. The reconstruction increases the density of active sites and reduces the CO binding strength on Pd surfaces, remarkably promoting the CO2 reduction to CO. A high CO Faradaic efficiency of 93 % is achieved with a site‐specific activity of 6.6 mA cm−2 at a moderate overpotential of 590 mV on the reconstructed 50 nm Pd nanosheets. Experimental and theoretical studies suggest the CO intermediate as a key factor driving the structural transformation during CO2 reduction. This study highlights the dynamic nature of defective metal nanosheets under reaction conditions and suggests new opportunities in surface engineering of 2D metal nanostructures to tune their electrocatalytic performance. A surface reconstruction is demonstrated on defect‐rich ultrathin Pd nanosheets during CO2 electroreduction. The pristine inactive basal surfaces are transformed into crumpled Pd(100)‐dominant active surfaces with reduced CO binding strength, promoting the CO2 conversion to CO with high selectivity and productivity.