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

作     者：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 

作者机构：College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China State Key Laboratory of Coal ConversionInstitute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China Syncat@Beijing Synfuels China Technology Co.LtdBeijing 101407China State Key Laboratory of Separation Membranes and Membrane ProcessesDepartment of Chemical Engineering Tianjin Polytechnic UniversityTianjin 300387China 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2018年第63卷第20期

页      面：1358-1363页

核心收录：

学科分类：07[理学] 08[工学] 

基　　金：supported by the National Natural Science Foundation of China(91645115,21473003,21673273,21473229,21821004,and 91545121) the National Basic Research Program of China(2013CB933100) the financial support of China Postdoctoral Science Foundation(2016M590216) the financial support of China Postdoctoral Science Foundation(2015M580011) National Thousand Young Talents Program of China Hundred-Talent Program of Chinese Academy of Sciences Shanxi Hundred-Talent Program 

主　　题：Wet-chemistry synthesis Bimetallic transition metal carbide Iron Cobalt Hydrogenation evolution reaction 

摘      要：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 Fe_5C_2 nanoparticles((Fe_(1-x)Cox)_5C_2 NPs) as highly active HER electrocatalysts in basic solution. The structure of(Fe_(1-x)Cox)_5C_2 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 Fe_5C_2.(Fe_(0.75) Co_(0.25))_5C_2 exhibited the best HER activity(174 mV for j = -10 mA/cm^2). 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 lowcost bimetallic TMCs based HER catalysts.