Fe5C2 nanoparticles as low-cost HER electrocatalyst: the importance of Co substitution

Siwei Li; Pengju Ren; Ce Yang; Xi Liu; Zhen Yin; Weizhen Li; Hanjun Yang; Jian Li; Xiaoping Wang; Yi Wang; Ruochen Cao; Lili Lin; Siyu Yao; Xiaodong Wen; Ding Ma

doi:10.1016/j.scib.2018.09.016

Fe₅C₂ nanoparticles as low-cost HER electrocatalyst: the importance of Co substitution

Sci Bull (Beijing). 2018 Oct 30;63(20):1358-1363. doi: 10.1016/j.scib.2018.09.016. Epub 2018 Sep 22.

Authors

Siwei Li¹, Pengju Ren², Ce Yang¹, Xi Liu³, Zhen Yin⁴, Weizhen Li¹, Hanjun Yang¹, Jian Li¹, Xiaoping Wang², Yi Wang², Ruochen Cao¹, Lili Lin¹, Siyu Yao¹, Xiaodong Wen⁵, Ding Ma⁶

Affiliations

¹ College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
² State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; Syncat@Beijing, Synfuels China Technology Co., Ltd, Beijing 101407, China.
³ State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; Syncat@Beijing, Synfuels China Technology Co., Ltd, Beijing 101407, China. Electronic address: liuxi@synfuelschina.com.cn.
⁴ State Key Laboratory of Separation Membranes and Membrane Processes, Department of Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
⁵ State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; Syncat@Beijing, Synfuels China Technology Co., Ltd, Beijing 101407, China. Electronic address: wxd@sxicc.ac.cn.
⁶ College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. Electronic address: dma@pku.edu.cn.

PMID: 36658907
DOI: 10.1016/j.scib.2018.09.016

Abstract

Constructing and understanding the doping effect of secondary metal in transition metal carbide (TMC) catalysts is pivotal for the design of low-cost hydrogen evolution reaction (HER) electrocatalysts. In this work, we developed a wet-chemistry strategy for synthesizing Co-modified Fe₅C₂ nanoparticles ((Fe_1-_xCo_x)₅C₂ NPs) as highly active HER electrocatalysts in basic solution. The structure of (Fe_1-_xCo_x)₅C₂ NPs was characterized by X-ray diffraction (XRD), extended X-ray absorption fine structure spectra (EXAFS) and scanning/transmission electron microscopy (S/TEM), indicating that the isomorphous substitution of cobalt in the lattice of Fe₅C₂. (Fe_0.75Co_0.25)₅C₂ exhibited the best HER activity (174 mV for j = -10 mA/cm²). Computational calculation results indicate that Co provides the most active site for HER. X-ray adsorption spectra (XAS) studies further suggested that the electron transfer in Fe-C bonds are enhanced by the substitution of Co, which modulates the hydrogen adsorption on the adjacent electronic-enriched carbon, and therefore promotes HER activity. Our results affirm the design of low-cost bimetallic TMCs based HER catalysts.

Keywords: Bimetallic transition metal carbide; Cobalt; Hydrogenation evolution reaction; Iron; Wet-chemistry synthesis.