Curvature of NCNTs induced selectivity of CO2 electroreduction into CO

Abstract

Abstract Nitrogen‐doped carbon nanotubes (NCNTs) are usually selective and robust electrocatalysts for CO2 reduction to CO in aqueous media. However, the electronic property of NCNTs is strongly dependent on their curvature, the change of curvature has a great impact on the electrocatalytic performance. Therefore, it is highly desirable to clarify the curvature effect of NCNTs for CO2RR performance. Herein, we investigated the CO2RR performances of NCNTs with different curvatures, which were obtained by doping N into CNTs under high temperatures. And low curvature of l‐NCNT‐1000 presented the highest CO FE (88.5%), which was much higher than that of the mid curvature of M‐NCNT‐1000 (71.1%) and the high curvature of S‐NCNT‐1000 (58%). According to density functional theory (DFT) calculations, the pyridine‐N site was considered a catalytic active site for CO2RR regardless of the low, mid or high curvature structure. Moreover, the low curvature surface of NCNTs had a relatively large binding energy with the HOCO* intermediate that is the principal intermediate for the CO2RR, thereby enhancing the catalytic activity of CO2 electroreduction to CO.

Keywords

• CO selectivity
• CO2 electroreduction
• curvature
• NCNTs