Carbon Black‐Supported Single‐Atom CoNC as an Efficient Oxygen Reduction Electrocatalyst for H<sub>2</sub>O<sub>2</sub> Production in Acidic Media and Microbial Fuel Cell in Neutral Media
Ying‐Xia Du, Qiao Yang, Wangting Lu, Qingyu Guan, Feifei Cao, Geng Zhang
Abstract
Abstract Single metal atom isolated in nitrogen‐doped carbon materials (MNC) are effective electrocatalysts for oxygen reduction reaction (ORR), which produces H 2 O 2 or H 2 O via 2‐electron or 4‐electron process. However, most of MNC catalysts can only present high selectivity for one product, and the selectivity is usually regulated by complicated structure design. Herein, a carbon black‐supported CoNC catalyst (CB@CoNC) is synthesized. Tunable 2‐electron/4‐electron behavior is realized on CB@Co‐N‐C by utilizing its H 2 O 2 yield dependence on electrolyte pH and catalyst loading. In acidic media with low catalyst loading, CB@CoNC presents excellent mass activity and high selectivity for H 2 O 2 production. In flow cell with gas diffusion electrode, a H 2 O 2 production rate of 5.04 mol h −1 g −1 is achieved by CB@CoNC on electrolyte circulation mode, and a long‐term H 2 O 2 production of 200 h is demonstrated on electrolyte non‐circulation mode. Meanwhile, CB@CoNC exhibits a dominant 4‐electron ORR pathway with high activity and durability in pH neutral media with high catalyst loading. The microbial fuel cell using CB@CoNC as the cathode catalyst shows a peak power density close to that of benchmark Pt/C catalyst.