Atomically Dispersed Nickel Coordinated with Nitrogen on Carbon Nanotubes to Boost Electrochemical CO<sub>2</sub> Reduction
Youngeun Kim, You Na Ko, Byeong‐Seon An, Jumi Hong, Ye Eun Jeon, Hak Joo Kim, Seunghyun Lee, Jinwoo Lee, Wonhee Lee
Abstract
Single-atom catalysts (SACs) are being widely developed for the CO 2 reduction reaction (CO 2 RR) because of their remarkable activity and selectivity. However, insufficient CO 2 RR performance and the poor long-term stability of the SACs remain obstacles to process scale-up. Herein, we explore Ni SACs (Ni-N/NCNT) under practical conditions using a zero-gap CO 2 electrolyzer for CO production. We demonstrate that the CO 2 RR performance of the Ni-N/NCNT results from the suitable Ni–N–C, which enhanced electron transfer and increased CO 2 adsorption. Furthermore, we propose a strategy for improving the CO 2 RR performance and long-term stability by focusing on the membrane electrode assembly (MEA) structure. A maximum Faradaic efficiency of 96.73% (at 2.1 V) and partial current density of 219.49 mA cm –2 (at 2.4 V) for CO production were obtained on the MEA with the Ni-N/NCNT catalyst and the Sustainion (Sust.) membrane. In addition, MEA with Sust. exhibited long-term stability at −100 mA cm –2 for over 60 h.