Copper coordinated with nitrogen in electrospun carbon nanofibers as a high-performance electrocatalyst for ORR

Abstract

Single-atom catalysts (SACs) have attracted much attention in the field of oxygen reduction reactions (ORR) as a result of their high selectivity and effective atom utilization. Cu SACs are particularly difficult to prepare since copper is prone to agglomeration, which leads to the formation of metal particles. In this study, using sodium copper chlorophyllin (SCC) as an organometallic copper source, carbon nanofibers incorporating Cu-N4 structures were prepared using electrospinning technology. This new type of Cu SAC has a huge surface area (1005.615 m2·g) and a 3D network structure, which are conducive to the exposure of more active sites as well as to electron conduction and material transport. Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy revealed that the Cu-N4 structure was preserved in the electrocatalyst, and was responsible for the catalytic activity towards the ORR. The Cu–N-CNFs exhibited higher catalytic activity and greater stability than commercial Pt/C in an alkaline medium, suggesting the possibility of using Cu SACs to replace commercial Pt/C electrocatalysts.