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>Iron Single Atoms on Graphene as Nonprecious Metal Catalysts for High‐Temperature Polymer Electrolyte Membrane Fuel Cells
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Iron Single Atoms on Graphene as Nonprecious Metal Catalysts for High‐Temperature Polymer Electrolyte Membrane Fuel Cells
Iron single atom catalysts (Fe SACs) are the best‐known nonprecious metal (NPM) catalysts for the oxygen reduction reaction (ORR) of polymer electrolyte membrane fuel cells (PEMFCs), but their practical application has been constrained by the low Fe SACs loading (<2 wt%). Here, a one‐pot pyrolysis method is reported for the synthesis of iron single atoms on graphene (FeSA‐G) with a high Fe SAC loading of ≈7.7 ± 1.3 wt%. The as‐synthesized FeSA‐G shows an onset potential of 0.950 V and a half‐wave potential of 0.804 V in acid electrolyte for the ORR, similar to that of Pt/C catalysts but with a much higher stability and higher phosphate anion tolerance. High temperature SiO2 nanoparticle‐doped phosphoric acid/polybenzimidazole (PA/PBI/SiO2) composite membrane cells utilizing a FeSA‐G cathode with Fe SAC loading of 0.3 mg cm−2 delivers a peak power density of 325 mW cm−2 at 230 °C, better than 313 mW cm−2 obtained on the cell with a Pt/C cathode at a Pt loading of 1 mg cm−2. The cell with FeSA‐G cathode exhibits superior stability at 230 °C, as compared to that with Pt/C cathode. Our results provide a new approach to developing practical NPM catalysts to replace Pt‐based catalysts for fuel cells.
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机译：铁单原子催化剂（Fe SACs）是用于聚合物电解质膜燃料电池（PEMFCs）的氧还原反应（ORR）的最著名的非贵金属（NPM）催化剂，但其实际应用受到低Fe SAC负载的限制（＜2重量％）。此处报道了一种单锅热解方法，用于在石墨烯（FeSA-G）上合成高铁SAC负载≈7.7±1.3 wt％的铁单原子。合成的FeSA-G在ORR的酸性电解液中显示的起始电位为0.950 V，半波电位为0.804 V，与Pt / C催化剂相似，但稳定性更高，且对磷酸盐的耐受性更高。使用FeSAC阴极和Fe SAC负载为0.3 mg cm −2 的FeSA-G阴极的高温SiO2纳米颗粒掺杂的磷酸/聚苯并咪唑（PA / PBI / SiO2）复合膜电池可提供325的峰值功率密度在230°C时mW cm −2 ，优于在Pt负载为1 mg cm −2 > −2 。与Pt / C阴极相比，具有FeSA-G阴极的电池在230°C的温度下具有出色的稳定性。我们的结果为开发实用的NPM催化剂替代燃料电池的Pt基催化剂提供了一种新方法。
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