Carbon Nanocage Supported Asymmetrically Coordinated Nickle Single-Atom for Enhanced CO2 Electroreduction in Membrane Electrode Assembly

Abstract

Designing efficient catalysts for operating CO2 electroreduction in membrane electrode assembly (MEA) faces significant obstacles. Herein, we propose an asymmetrically coordinated Ni SAC featuring axial Br coordination at NiN4Br sites anchoring onto hollow Br/N co-doped carbon nanocages, achieved through a NaBr-assisted confined-pyrolysis strategy. The Ni-NBr-C exhibits a high CO Faradaic efficiency (FECO> 97%) over the current density range of 50 to 350 mA cm−2 in the MEA device. Furthermore, Ni-NBr-C shows a stable cell voltage of 2.66 ± 0.2 V while delivering a large current density of 350 mA cm−2 over an 85-hour long-term operation, demonstrating its potential for industrial-scale applications. Advanced characterization techniques and theoretical calculations reveal that the coordination and doping of Br enhance the intrinsic activity but also highlighted that the unique pore structure improves mass transfer efficiency.