Sn–Fe Dual-Metallic Nanoparticles on S,N-Codoped g-C₃N₄-Derived Tubular Carbon as an Efficient Bifunctional Catalyst for Oxygen Reduction Reaction and Oxygen Evolution Reaction
Abstract
Developing cost-effective, high-performance bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial for advanced clean energy technologies. This work details Sn−Fe bimetallic nanoparticles anchored on S,N-codoped graphitic carbon nitride (C₃N₄)-derived tubular carbon (SnFe/SNC_T), synthesized via a facile pyrolysis method at 850 °C (SnFe/SNC_850). The optimized SnFe/SNC_850 catalyst, characterized by a distinct bamboo-like tubular morphology, demonstrates superior ORR activity with a half-wave potential (E₁/₂) of 0.86 V vs RHE in 0.1 M KOH, surpassing commercial Pt/C (0.82 V). Furthermore, it exhibits excellent OER performance, requiring only 340 mV overpotential to achieve 10 mA cm⁻², and displays remarkable overall bifunctionality. When SnFe/SNC_850 is integrated into an anion exchange membrane fuel cell (AEMFC), it delivers a peak power density of 277 mW cm⁻², significantly outperforming Pt/C-based cells (168 mW cm⁻²). The catalyst also demonstrates exceptional durability, with only 20 mV of E₁/₂ decay after 30,000 cycles, compared to 50 mV for Pt/C. This enhanced performance is attributed to the synergistic interplay between Fe−Nₓ/Fe−Sₓ active sites and intermetallic Fe₃SnC/FeS domains. These findings establish SnFe/SNC_850 as a highly promising nonprecious-metal bifunctional electrocatalyst for practical energy-conversion applications.
摘要
開發具成本效益、高效能的雙功能性電觸媒，以驅動氧還原反應（ORR）與氧析出反應（OER），對先進潔淨能源技術至關重要。本工作成功研發 Sn-Fe 雙金屬奈米粒子，錨定於硫、氮共參雜之石墨氮化碳（g-C₃N₄）衍生管狀碳材上（命名為 SnFe/SNC_T），並以簡便熱解法在 850 °C 下合成（SnFe/SNC_850）。此優化觸媒具有獨特的竹節狀管狀結構，展現優異的 ORR 活性：在 0.1 M KOH 中之半波電位（E₁/₂）達 0.86 V（相對於 RHE），超越商用 Pt/C 觸媒（0.82 V）。此外，其 OER 性能同樣出色，僅需 340 mV 過電位即可達到 10 mA cm⁻²，顯示卓越的雙功能性。將 SnFe/SNC_850 整合至陰離子交換膜燃料電池（AEMFC）後，峰值功率密度達 277 mW cm⁻²，遠優於 Pt/C 基電池（168 mW cm⁻²）。此觸媒亦展現出色的耐久性：經 30,000 次循環後，半波電位衰減僅 20 mV，相較之下 Pt/C 衰減達 50 mV。此卓越性能歸因於 Fe−Nₓ/Fe−Sₓ 活性位點與金屬間化合物 Fe₃SnC/FeS 結構之協同作用。本研究成功證明 SnFe/SNC_850 作為極具潛力之非貴金屬雙功能電觸媒。
🔬 重要發現
優異 ORR 活性，超越商用 Pt/C：SnFe/SNC_850 在 0.1 M KOH 中之 ORR 半波電位 E₁/₂ 達 0.86 V（vs RHE），優於商用 Pt/C（0.82 V），為非貴金屬觸媒樹立新標竿。
SnFe/SNC_850 achieves a half-wave potential (E₁/₂) of 0.86 V vs RHE in 0.1 M KOH, surpassing commercial Pt/C (0.82 V).
出色 OER 性能，低過電位達成高電流：SnFe/SNC_850 之 OER 僅需 340 mV 過電位即可達到 10 mA cm⁻²，展現優異的雙功能催化特性。
The OER requires only 340 mV overpotential to reach 10 mA cm⁻², demonstrating excellent bifunctional catalytic performance.
AEMFC 峰值功率密度大幅超越 Pt/C：以 SnFe/SNC_850 為觸媒之 AEMFC 峰值功率密度達 277 mW cm⁻²，顯著超越 Pt/C 基電池（168 mW cm⁻²）。
SnFe/SNC_850-based AEMFC delivers a peak power density of 277 mW cm⁻², significantly outperforming Pt/C-based cells (168 mW cm⁻²).
卓越耐久性，30,000 次循環後性能衰減極小：經 30,000 次加速耐久性測試後，SnFe/SNC_850 之 E₁/₂ 衰減僅 20 mV，遠低於 Pt/C 之 50 mV，顯示其卓越的長期穩定性。
After 30,000 cycles, SnFe/SNC_850 exhibits only 20 mV of E₁/₂ decay, far lower than Pt/C's 50 mV.
Fe−Nₓ/Fe−Sₓ 與 Fe₃SnC/FeS 協同效應：ORR/OER 活性提升之關鍵機制為 Fe−Nₓ/Fe−Sₓ 活性位點與金屬間化合物 Fe₃SnC/FeS 結構之協同耦合。
The enhanced activity originates from synergistic interplay between Fe−Nₓ/Fe−Sₓ active sites and intermetallic Fe₃SnC/FeS domains.
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