Large specific surface area S-doped Fe–N–C electrocatalysts derived from Metal–Organic frameworks for oxygen reduction reaction

• Published in: Progress in natural science Vol. 30; no. 6; pp. 896 - 904
• Main Authors: Yan, Xiaohui, Li, Xiaolin, Fu, Cehuang, Lin, Chen, Hu, Huanming, Shen, Shuiyun, Wei, Guanghua, Zhang, Junliang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2020
• Subjects: Acidic and alkaline medium; Co-doping; Fuel cells; Non-precious metal catalyst; Oxygen reduction reaction; Acidic and alkaline medium; Non-precious metal catalyst; Fuel cells; Oxygen reduction reaction; Co-doping
• ISSN: 1002-0071
• DOI: 10.1016/j.pnsc.2020.10.018

It is highly desired but challenging to develop platinum group metal-free electrocatalysts for oxygen reduction reaction (ORR), which can promote the commercialization of fuel cell technology. To achieve this target, we report a one-step doping method to prepare S-doped Fe–N–C catalysts using zeolite imidazole framework (ZIF-8) and iron (III) thiocyanate (Fe(SCN)3) as precursor. Different from conventional doping approach, i.e. physical mixing, Fe(SCN)3 is in-situ added during ZIF-8 formation which would encapsulate Fe(SCN)3 molecules inside ZIF-8 to avoid structure destruction and create potential replacement of Zn ions by Fe ions to form uniform Fe–N4 complexes. As a result, the prepared S-doped Fe–N–C catalysts own large specific surface areas with a maximum value of 1326 ​m2 ​g−1 and a dual-scale porous structure that benefits mass transport. Significantly, the composition-optimized catalyst exhibits superior ORR activity in both 0.1 ​M HClO4 electrolyte and 0.1 ​M KOH electrolyte, in which the half-wave potential reaches 0.81 ​V and 0.92 ​V (vs. RHE), respectively. Remarkable stability is also attained, which loses 2 ​mV only after 10000 potential cycles in O2-saturated 0.1 ​M HClO4 and remains almost constant in O2-saturated 0.1 ​M KOH, surpassing commercial Pt/C catalyst in both acidic and alkaline medium. [Display omitted] •S-doped Fe–N–C electrocatalysts were prepared via one-step doping method.•Prepared catalysts own ultrahigh specific surface area (1062–1326 ​m2 ​g−1).•The catalysts show good activity and durability in both acidic and alkaline medium.