Hydrogen peroxide (H₂O₂) is an important oxidant with uses in different industrial sectors. Currently used methods for the large-scale production of H₂O₂ can suffer from drawbacks such as high energy use and safety concerns. An electrochemical two-electron oxygen reduction reaction (2e^– ORR) could be a useful, green alternative for the production of H₂O₂ from oxygen and water. However, this requires suitable electrocatalysts that promote the reaction in an efficient and selective manner. Metal-free carbon-based materials can be useful candidates for this, but they usually work best in alkaline media, where H₂O₂ can be unstable.

Wangqiang Shen, Kun Guo, Jian Zhang, Xing Lu, Huazhong University of Science and Technology, Wuhan, China, and colleagues have developed a nitrogen-doped carbon nanomaterial that is rich in pentagonal defects (PD/N–C) and can be used for H₂O₂ electrosynthesis under acidic conditions. The team started from the fullerene C₆₀, which was subjected to pyrolysis at 1000 °C for 2 h under an argon atmosphere to give pentagonal-defect-enriched carbons. This was followed by treatment with ammonia to obtain the desired pentagonal-defect-enriched nitrogen-doped carbons.

According to the researchers, the combined effects of the pentagonal substructures and the nitrogen doping improve *OOH adsorption and, thus, promote H₂O₂ production. The PD/N–C catalyst showed high ORR activity and selectivity for the two-electron oxygen reduction reaction, as well as stability in acidic electrolytes. Used in a flow cell, PD/N–C provides a high Faraday efficiency and a high H₂O₂ yield rate. Overall, the work could be useful for the design and synthesis of efficient, acid-resistant carbon electrocatalysts for the production of H₂O₂.

• A Pentagonal Defect-Rich Metal-Free Carbon Electrocatalyst for Boosting Acidic O₂ Reduction to H₂O₂ Production,
  Chang Zhang, Wangqiang Shen, Kun Guo, Mo Xiong, Jian Zhang, Xing Lu,
  J. Am. Chem. Soc. 2023.
  https://doi.org/10.1021/jacs.3c00689