Ao Xiang, Zhang Wei, Li Zhishan, Li Jian-Gang, Soule Luke, Huang Xing, Chiang Wei-Hung, Chen Hao Ming, Wang Chundong, Liu Meilin, Zeng Xiao Cheng
School of Optical and Electronic Information , Huazhong University of Science and Technology , Wuhan 430074 , China.
School of Materials Science & Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States.
ACS Nano. 2019 Oct 22;13(10):11853-11862. doi: 10.1021/acsnano.9b05913. Epub 2019 Sep 16.
Single-atom catalysts (SACs) have emerged as one of the most promising alternatives to noble metal-based catalysts for highly efficient oxygen reduction reaction (ORR). While SACs can offer notable benefits in terms of lowering overall catalyst cost, there is still room for improvement regarding catalyst activity. To this end, we designed and successfully fabricated an ORR electrocatalyst in which atomic clusters are embedded in an atomically dispersed Fe-N-C matrix (Fe@Fe-N-C), as shown by comprehensive measurements using aberration-corrected scanning transmission electron microscopy (AC-STEM) and X-ray absorption spectroscopy (XAS). The half-wave potential of Fe@Fe-N-C is 0.912 V (versus reversible hydrogen electrode (RHE)), exceeding that of commercial Pt/C (0.897 V), Fe-N-C (0.844 V), as well as the half-wave potentials of most reported non-platinum-group metal catalysts. The ORR activity of the designed catalyst stems from single-atom active centers but is markedly enhanced by the presence of Fe nanoclusters, as confirmed by both experimental measurements and theoretical calculations.
单原子催化剂（SACs）已成为用于高效氧还原反应（ORR）的最有前景的贵金属基催化剂替代品之一。虽然SACs在降低总体催化剂成本方面可带来显著益处，但在催化剂活性方面仍有改进空间。为此，我们设计并成功制备了一种ORR电催化剂，其中原子团簇嵌入原子分散的Fe-N-C基体（Fe@Fe-N-C）中，这通过使用像差校正扫描透射电子显微镜（AC-STEM）和X射线吸收光谱（XAS）的综合测量得以证明。Fe@Fe-N-C的半波电位为0.912 V（相对于可逆氢电极（RHE）），超过了商业Pt/C（0.897 V）、Fe-N-C（0.844 V）以及大多数已报道的非铂族金属催化剂的半波电位。经实验测量和理论计算证实，所设计催化剂的ORR活性源于单原子活性中心，但因Fe纳米团簇的存在而显著增强。
