Amine‐Functionalized Carbon Nanodot Electrocatalysts Converting Carbon Dioxide to Methane
Ram Manohar Yadav, Zhengyuan Li, Tianyu Zhang, Onur Sahin, Soumyabrata Roy, Guanhui Gao, Huazhang Guo, Róbert Vajtai, Liang Wang, Pulickel M. Ajayan, Jingjie Wu
Abstract
Abstract The electrochemical conversion of carbon dioxide (CO 2 ) to methane (CH 4 ), which can be used not only as fuel but also as a hydrogen carrier, has drawn great attention for use in supporting carbon capture and utilization. The design of active and selective electrocatalysts with exceptional CO 2 ‐to‐CH 4 conversion efficiency is highly desirable; however, it remains a challenge. Here a molecular tuning strategy−in situ amine functionalization of nitrogen‐doped graphene quantum dots (GQDs) for highly efficient CO 2 ‐to‐CH 4 conversion is presented. Amine functionalized nitrogen‐doped GQDs achieve a CH 4 Faradic efficiency (FE) of 63% and 46%, respectively, at CH 4 partial current densities of 170 and 258 mA cm −2 , approximating to or even outperforming state‐of‐the‐art Cu‐based electrocatalysts. These GQDs also convert CO 2 to C 2 products mainly including C 2 H 4 and C 2 H 5 OH with a maximum FE of ≈10%. A systematic analysis reveals that the CH 4 yield varies linearly with amine group content, whereas the C 2 production rate is positively dependent on pyridinic N dopant content. This work provides insight into the rational design of carbon catalysts with CO 2 ‐to‐CH 4 conversion efficiency at the industrially relevant level.