Selective Etching of Nitrogen‐Doped Carbon by Steam for Enhanced Electrochemical CO2 Reduction

Abstract Nitrogen‐doped carbon structures have recently been demonstrated as a promising candidate for electrocatalytic CO 2 reduction, while in the meantime the pyridinic and graphitic nitrogen atoms also present high activities for electroreduction of water. Here, an etching strategy that uses hot water steam to preferentially bind to pyridinic and graphitic nitrogen atoms and subsequently etch them in carbon frameworks is reported. As a result, pyrrolic nitrogen atoms with low water affinity are retained after the steam etching, with a much increased level of among all nitrogen species from 22.1 to 55.9%. The steam‐etched nitrogen‐doped carbon catalyst enables excellent electrocatalytic CO 2 reduction performance but low hydrogen evolution reaction activity, suggesting a new approach for tuning electrocatalyst activity.