2020年12月7日 · From in situ 57 Fe Mössbauer spectroscopy in inert gas coupled to calculations of the Mössbauer signature of FeN x moieties in different electronic states, we identify S1 to be a high-spin FeN 4 C...

2020年12月1日 · In this study, FeNC electrocatalysts with varying Fe/C ratios show different Fe@C/Fe–Nx ratios and ORR activities. Increasing the carbon content increases the Fe–N x site density while decreasing the size of the Fe nanoparticles and the thickness of the carbon coating layer, thus enhancing the ORR activity.

2021年1月18日 · FeNC catalysts are the most promising substitutes for Pt-based catalysts for the oxygen reduction reaction in proton exchange fuel cells. However, it remains unclear which FeN 4 moieties contribute to the reaction mechanism and in which way.

2023年9月1日 · X-ray absorption spectroscopy (XAS) was used to study the electronic states and coordination environment of each component. The X-ray absorption near edge structure (XANES, Fig. 2 c) spectra at the Pt L3-edge show that PtO 2 has strong white line (WL) intensity, which proves the existence of Pt oxidation state. However, the WL strength of CNT ...

2021年6月10日 · Herein we implement a chemical vapour deposition (CVD) synthesis, flowing iron chloride vapour over a bed of Zn–N–C material, to preferentially form accessible Fe–N 4 sites with self-optimized Fe...

2024年8月26日 · In this work, we employ in-situ X-ray absorption near-edge structure (XANES) to monitor the active-site degradation byproducts of an atomically dispersed Fe−N−C ORR catalyst under a H 2 /O 2 -operating PEMFC at 90 % relative humidity and 80 °C. For this, stability tests were carried out at two constant cell voltages, namely 0.4 and at 0.8 V.

2021年4月1日 · The identification of the iron species on Fe–N-DCB, namely Fe environment, coordination and oxidation and their evolution after the ASTs has been accomplished by the Fe K-edge XAS, using Fe Phthalocyanine (with Fe 2+ coordinated to N in FeN 4), Fe 3 C, Fe-oxides and metallic Fe as standards.

2023年2月4日 · Atomic Fe in N-doped carbon (FeNC) electrocatalysts for oxygen (O 2) reduction at the cathode of proton exchange membrane fuel cells are the most promising alternative to platinum-group-metal catalysts. Despite recent progress on atomic FeNC O 2 reduction, their controlled synthesis and stability for practical applications remain challenging. A ...

通过XPS和XAS表征证实了PtFe合金和FeN4位点间存在强电子耦合相互作用，FeNC基底上的FeN4位点能够有效锚定PtFe合金，抑制它们的聚集，而PtFe合金又可以反过来抑制FeNC基底中FeN4位点的浸出（FeN4浸出速率由1.5‰/cycle降低至0.1‰/cycle）。

为此，武刚教授团队开发了一种高稳定性、高活性Fe-N-C的制备方法，通过调变FeN4位点的碳结构和配位环境，实现了所合成的催化剂在保证高活性的同时兼具出色的稳定性。 研究首先采用高温处理包含Fe2O3纳米颗粒的ZIF-8前驱体，随后，关键的高温NH4Cl处理为其提供丰富的缺陷。 所制备的Fe-N-C催化剂（Fe-AC）具有大量高活性的S1位点，在酸性条件下，半波电位（E1/2）高达0.915 VRHE，显著高于商业Pt/C催化剂；在燃料电池测试条件下，其面积比活性高达41.1 mA …