Coaxial Metal‐Nitrogen–Carbon Single‐Atom Catalysts Boost Acid Hydrogen Peroxide Production

Abstract

Electrosynthesis of hydrogen peroxide (H2O2) by two‐electron oxygen reduction reaction (2e− ORR) under acidic conditions is promising. However, constructing a highly efficient acid‐resistant 2e− ORR electrocatalyst is critical but challenging. Herein, a coaxial cobalt single‐atom catalyst on carbon nanotubes (CoSA‐N‐C/CNTs) is designed and synthesized by an ingenious separation chemical vapor deposition (SCVD) strategy, which achieves higher ORR activity, dominated 2e− selectivity, and superior stability in acid, compared to the counterpart nanoparticle catalyst prepared by traditional mixture pyrolysis. The as‐assembled electrode using CoSA‐N‐C/CNTs catalyst demonstrates a high H2O2 yield in excess of 2000 mmol gcat−1 h−1 with a Faraday efficiency of >90% over 100 h without decay in a flow cell, as superior to the most reported acidic H2O2 production catalysts. Experimental characterization and theoretical calculations reveal that such excellent 2e− ORR performance of CoSA‐N‐C/CNTs originate from the combined advantages of strongly coupled coaxial core–shell structure and highly dispersed single‐atom property. Most importantly, a series of other coaxial transition metal single‐atom catalysts (MSA‐N‐C/CNTs, M = Fe, Cu, or Ni) are prepared through this SCVD strategy, and they all show enhanced ORR performance, demonstrating universality.