Pyrolysis-Free Mechanochemical Conversion of Small Organic Molecules into Metal-Free Heteroatom-Doped Mesoporous Carbons for Efficient Electrosynthesis of Hydrogen Peroxide
Na Yang, Xiang Zhu, Xiang Zhu, Guofeng Wang, Lulu Zhou, Xiaoxiao Zhu, Xiaoxiao Zhu, Jiaqi Pan, Wei Yu, Chungu Xia, Chengcheng Tian
Abstract
The synthesis of heteroatom-doped porous carbons for efficient electrochemical production of hydrogen peroxide (H 2 O 2 ) through two-electron (2e – ) oxygen reduction reaction (ORR) has attracted increasing research attention since it offers a promising renewable substitute for the traditional complex energy-intensive anthraquinone process. Herein, a novel pyrolysis-free mechanochemical approach was developed for straightforward conversion of small organic molecules into metal-free heteroatom-doped mesoporous carbons (HMCs), where the uniqueness of this one-pot ball-milling technique not only exceeds the limit of volatilities of traditional carbonaceous precursors but also eliminates the need for any additional mesoporous templates. The abundance of molecular precursors (up to 23 different molecules) provides a facile means to introduce a wide variety of heteroatoms (B, N, O, P, S, F, Cl, etc.) into the resultant carbon materials, accompanied by in situ formation of rich mesopores. As a result, the resulting N/O co-doped mesoporous carbon with the highest Brunauer–Emmett–Teller (BET) surface area of 1238 m 2 g –1 exhibits exceptional H 2 O 2 selectivity of 95.2% in 0.1 M KOH solution at 0.70 V (vs. reversible hydrogen electrode, RHE) and a large H 2 O 2 production rate of ca. 265 mmol g cat. –1 h –1, ranking at the top among all metal-free carbonaceous electrocatalysts. We anticipate our findings will facilitate new possibilities for the development of mesoporous carbons for electrocatalytic applications.