The structural tailoring of pores is essential to high-performance Fe/N/C electrocatalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. Current strategies for pore structure engineering are usually accompanied with a drastic change of the intrinsic activity-related surface, which may mask the real effects of the porous structure on ORR activity. Herein, a mild carbon dioxide (CO₂) etching method was used to flexibly tailor the pore structure of Fe/N/C electrocatalysts without drastic changes in their surface structure and property. In this way, via employing the Fe/N/C electrocatalysts as a model, the intrinsic impact of the pore structure on ORR activity was revealed. In addition, the CO₂ etching method developed a high-quality electrocatalyst (sample Fe/N/C–5% CO₂) with polarization performance exceeding that of the commercial Pt/C catalyst in the fuel cell working voltage region (>0.65 V). This work will promote the ongoing intensive studies on the rational design of the pore structures in the Fe/N/C electrocatalysts.

中文翻译：

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一种温和的 CO2 蚀刻方法来定制质子交换膜燃料电池中无铂氧还原催化剂的孔结构

孔的结构调整对于用于质子交换膜燃料电池中氧还原反应 (ORR) 的高性能 Fe/N/C 电催化剂至关重要。当前的孔结构工程策略通常伴随着与内在活性相关的表面的剧烈变化，这可能掩盖了多孔结构对 ORR 活性的真实影响。在此，采用温和的二氧化碳 (CO ₂ ) 蚀刻方法灵活地调整 Fe/N/C 电催化剂的孔结构，而不会对其表面结构和性能产生剧烈变化。通过这种方式，通过使用 Fe/N/C 电催化剂作为模型，揭示了孔结构对 ORR 活性的内在影响。此外，CO ₂蚀刻方法开发了一种高质量的电催化剂（样品 Fe/N/C–5% CO ₂），其极化性能在燃料电池工作电压范围内（> 0.65 V）超过了商用 Pt/C 催化剂。这项工作将促进对 Fe/N/C 电催化剂中孔结构合理设计的深入研究。