Atomically Dispersed Nickel Coordinated with Nitrogen on Carbon Nanotubes to Boost Electrochemical CO2 Reduction

Abstract

Single-atom catalysts (SACs) are being widely developedfor theCO(2) reduction reaction (CO2RR) because of theirremarkable activity and selectivity. However, insufficient CO2RR performance and the poor long-term stability of the SACsremain obstacles to process scale-up. Herein, we explore Ni SACs (Ni-N/NCNT)under practical conditions using a zero-gap CO2 electrolyzerfor CO production. We demonstrate that the CO2RR performanceof the Ni-N/NCNT results from the suitable Ni-N-C, whichenhanced electron transfer and increased CO2 adsorption.Furthermore, we propose a strategy for improving the CO2RR performance and long-term stability by focusing on the membraneelectrode assembly (MEA) structure. A maximum Faradaic efficiencyof 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 theMEA with the Ni-N/NCNT catalyst and the Sustainion (Sust.) membrane.In addition, MEA with Sust. exhibited long-term stability at -100mA cm(-2) for over 60 h.