Nitrogen‐Doped Carbon Nanotube Arrays for High‐Efficiency Electrochemical Reduction of CO2: On the Understanding of Defects,Defect Density,and Selectivity |
| |
Authors: | Pranav P Sharma Dr Jingjie Wu Dr Ram Manohar Yadav Mingjie Liu Christopher J Wright Dr Chandra Sekhar Tiwary Prof Boris I Yakobson Prof Jun Lou Prof Pulickel M Ajayan Prof Xiao‐Dong Zhou |
| |
Institution: | 1. Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (USA);2. Department of Materials Science and NanoEngineering, Rice University Houston, TX 77005 (USA) |
| |
Abstract: | Nitrogen‐doped carbon nanotubes (NCNTs) have been considered as a promising electrocatalyst for carbon‐dioxide‐reduction reactions, but two fundamental chemistry questions remain obscure: 1) What are the active centers with respect to various defect species and 2) what is the role of defect density on the selectivity of NCNTs? The aim of this work is to address these questions. The catalytic activity of NCNTs depends on the structural nature of nitrogen in CNTs and defect density. Comparing with pristine CNTs, the presence of graphitic and pyridinic nitrogen significantly decreases the overpotential (ca. ?0.18 V) and increases the selectivity (ca. 80 %) towards the formation of CO. The experimental results are in congruent with DFT calculations, which show that pyridinic defects retain a lone pair of electrons that are capable of binding CO2. However, for graphitic‐like nitrogen, electrons are located in the π* antibonding orbital, making them less accessible for CO2 binding. |
| |
Keywords: | carbon dioxide fixation carbon nanotubes carbon monoxide selectivity electrochemistry nitrogen defects |
|
|