Hydrogen peroxide (H₂O₂) has a wide range of applications in paper and pulp, textile, wastewater treatment etc. The electrochemical strategy for on-site production of H₂O₂ via two-electron oxygen reduction reaction (2e^- ORR) is a promising alternative. However, the highly sluggish kinetics of 2e- ORR process and the competitive 4e- ORR to H₂O severely decrease the yield of H₂O₂. Therefore, development of electrocatalysts with high activity and selectivity of 2e^- ORR is critically important for high-efficiency electrosynthesis of H₂O₂.

Recently, scientists from the Institute of Solid State Physics (ISSP) of the Hefei Institutes of Physical Science (HFIPS) synthesized a nitrogen-coordinated Co single atom catalyst with superior two-electron oxygen reduction reaction (2e- ORR) performance toward H₂O₂ production. 

In this work, they fabricated a nitrogen-coordinated Co single atom catalyst (Co-SAs/NC) using the coordination regulation strategy. The Co-Nx active sites and nearby oxygen functional groups have a synergetic effect that can promote the H₂O₂ activity and selectivity.

It's proved that when using Co-SAs/NC as the electrocatalyst, a H₂O₂ yield of 38.1±1.5 mmol gcat^-1 h^-1 or (17318±682 mmol gCo^-1 h^-1) with a faradaic efficiency of ~72.1±4.2% at 0.5 V (vs. RHE) could be achieved in 0.1 M KOH.  

These new findings would be very helpful for designing and developing high-efficiency 2e^- ORR electrocatalysts for H₂O₂ production.

This work was financially supported by the Natural Science Foundation of China, the China Postdoctoral Science Foundation, and the CASHIPS Director's Fund.

Fig. 1. Schematic illustration of the synthetic process, TEM, aberration-corrected HAADF-STEM and corresponding elemental mapping images of Co-SAs/NC. (Image by HFIPS) 

Fig. 2. LSV curves, calculated H₂O₂ selectivity and electron transfer number (n) of Co-SAs/NC at 1600 rpm in different O_2-saturated electrolytes and at different rotation speeds in 0.1 M KOH. (Image by HFIPS)