Searching for highly efficient bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) using nonnoble metal‐based catalysts is essential for the development of many energy conversion systems, including rechargeable fuel cells and metal–air batteries. Here, Co_9–xFe_xS₈/Co,Fe‐N‐C hybrids wrapped by reduced graphene oxide (rGO) (abbreviated as S‐Co_9–xFe_xS₈@rGO) are synthesized through a semivulcanization and calcination method using graphene oxide (GO) wrapped bimetallic zeolite imidazolate framework (ZIF) Co,Fe‐ZIF (CoFe‐ZIF@GO) as precursors. Benefiting from the synergistic effect of OER active CoFeS and ORR active Co,Fe‐N‐C in a single component, as well as high dispersity and enhanced conductivity derived from rGO coating and Fe‐doping, the obtained S‐Co_9–xFe_xS₈@rGO‐10 catalyst shows an ultrasmall overpotential of ≈0.29 V at 10 mA cm⁻² in OER and a half‐wave potential of 0.84 V in ORR, combining a superior oxygen electrode activity of ≈0.68 V in 0.1 m KOH.

中文翻译：

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氧化石墨烯包裹的Co9–xFexS8 / Co，Fe‐N‐C复合材料作为双功能电催化剂，用于氧的还原和释放

使用非贵金属基催化剂寻找用于氧还原反应（ORR）和氧释放反应（OER）的高效双功能电催化剂对于开发许多能量转换系统至关重要，包括可充电燃料电池和金属空气电池。在这里，Co _{9– x} Fe _x S ₈ / Co，Fe‐N‐C杂化物被还原的氧化石墨烯（rGO）包裹（缩写为S‐Co _{9– x} Fe _x S ₈（rGO）是通过半硫化和煅烧方法合成的，使用氧化石墨烯（GO）包裹的双金属咪唑酸酯骨架（ZIF）Co，Fe-ZIF（CoFe-ZIF @ GO）作为前体。得益于OER活性CoFeS和ORR活性Co，Fe-N-C在单一组分中的协同作用，以及rGO涂层和Fe掺杂带来的高分散性和增强的电导率，获得的S-Co _{9– x} Fe _x S ₈ @ rGO-10催化剂在OER中在10 mA cm ^-2时显示出超小的超电势，≈0.29 V，在ORR中显示出0.84 V的半波电势，在0.1 m KOH中具有卓越的氧电极活性≈0.68V 。