Enriching Atomic Cobalt in an Ultrathin Porous Carbon Shell for Enhanced Electrocatalysis

Developing nonprecious electrocatalysts operating in acidic and alkaline media for an oxygen reduction reaction (ORR) is essential for sustainable energy technologies. Increasing the metal active site density is an effective strategy to enhance the activity, but it remains challenging because of metal sintering during pyrolysis. Here, we report a novel strategy of enriching atomically dispersed cobalt species in nitrogen-doped carbon for improving the electrocatalytic performance. A hollow carbon nanosphere with reduced shell thickness was obtained by taking advantage of the carbothermic reaction between carbon and ZnO template, and the resulting cobalt enrichment in the ultrathin carbon shell leads to an increase of the density of Co atoms. Together with advantageous microstructure features such as high surface area and multiscale porosity, the corresponding catalyst demonstrated promising oxygen reduction reaction performance in strong acidic and alkaline electrolytes and has two times higher kinetic current density than the nonenriched one. The present work provides an attractive and facile route to engineer active site in electrocatalysts.

Automated summary

In this study, a novel strategy of enriching atomically dispersed cobalt species in nitrogen-doped carbon was reported, resulting in an increase of Co atom density in the ultrathin carbon shell. The hollow carbon nanosphere with reduced shell thickness obtained by a carbothermic reaction between carbon and ZnO template, demonstrated promising oxygen reduction reaction performance in both strong acidic and alkaline electrolytes.