Regulable pyrrolic-N-doped carbon materials as an efficient electrocatalyst for selective O2 reduction to H2O2

Abstract

As a successful alternative to the complex and dangerous anthraquinone process, a simple and safe method for the efficient preparation of hydrogen peroxide is to use the electrochemical two-electron oxygen reduction reaction (2e⁻ ORR) process. Herein, we report a facile approach to achieving metal-free nitrogen-doped carbon material electrocatalysts (N-CMCs) using cheap and easily available raw materials, which also have an excellent electrochemical 2e⁻ ORR catalytic performance and selectivity for hydrogen peroxide (H₂O₂). The as-fabricated nitrogen-doped carbon material electrocatalysts (named as N-CMC-1 : 5) deliver the high H₂O₂ selectivity of over 80% in a wide potential range from 0.30 to 0.70 V vs. RHE, where the highest H₂O₂ selectivity can reach 81.4% at 0.42 V vs. RHE. X-ray photoelectron spectroscopy and electrochemical analyses reveal that the content of pyrrolic-N in the catalysts has a positive effect on the 2e⁻ ORR activity. When the catalyst contains more pyrrolic-N, the catalyst demonstrates a better 2e⁻ ORR performance and H₂O₂ selectivity in alkaline medium, as well as the long-term stability of the catalyst.