A Pentagonal Defect-Rich Metal-Free Carbon Electrocatalyst for Boosting Acidic O₂ Reduction to H₂O₂ Production

Abstract

Metal-free carbon-based materials are considered one of the most promising two-electron oxygen reduction reaction (2e^- ORR) electrocatalysts for the green synthesis of hydrogen peroxide (H₂O₂). However, most reported carbon electrocatalysts perform much more effectively in alkalis than in acids. Herein, by creatively using fullerene (C₆₀) as the precursor subject to ammonia treatment, we designed and synthesized a pentagonal defect-rich nitrogen-doped carbon nanomaterial (PD/N-C). It achieves outstanding ORR activity, 2e^- selectivity, and stability in acidic electrolytes, surpassing the benchmark PtHg₄ alloy catalyst. Impressively, the flow cell based on the PD/N-C catalyst achieves nearly 100% Faraday efficiency with a remarkable H₂O₂ yield, representing the best improvement among all the metal-free catalysts. Experimental and theoretical results reveal that such superb 2e^- ORR performance of PD/N-C originates from the synergism between pentagonal defects and nitrogen dopants. This work presents an effective strategy for the design and construction of highly efficient acid-resistant carbon electrocatalysts for H₂O₂ production and beyond.