Singlet Oxygen Induced Site-Specific Etching Boosts Nitrogen-Carbon Sites for High-Efficiency Oxygen Reduction.

Abstract

Targeted construction of carbon defects near the N dopants is an intriguing but challenging way to boost the electrocatalytic activity of N-doped carbon toward oxygen reduction reaction (ORR). Here, we report a novel site-specific etching strategy that features targeted anchoring of singlet oxygen (1 O2 ) on the N-adjacent atoms to directionally construct topological carbon defects neighboring the N dopants in N-doped carbon (1 O2 -N/C). This 1 O2 -N/C exhibits the highest ORR half-wave potential of 0.915 VRHE among all the reported metal-free carbon catalysts. Pyridinic-N bonded with a carbon pentagon of the neighboring topological carbon defects is identified as the primary active configuration, rendering enhanced adsorption of O2 , optimized adsorption energy of the ORR intermediates, and a significantly decreased total energy barrier for ORR. This 1 O2 -induced site-specific etching strategy is also applicable to different precursors, showing a tremendous potential for targeted construction of high-efficiency active sites in carbon-based materials.