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Molybdenum Carbide Nanoparticles Coated into the Graphene Wrapping N‐Doped Porous Carbon Microspheres for Highly Efficient Electrocatalytic Hydrogen Evolution Both in Acidic and Alkaline Media
Advanced Science ( IF 14.3 ) Pub Date : 2018-01-03 , DOI: 10.1002/advs.201700733
Huifang Wei 1 , Qiaoya Xi 1 , Xi'an Chen 1 , Daying Guo 1 , Feng Ding 1 , Zhi Yang 1 , Shun Wang 1 , Juan Li 1 , Shaoming Huang 1, 2
Affiliation  

Molybdenum carbide (Mo2C) is recognized as an alternative electrocatalyst to noble metal for the hydrogen evolution reaction (HER). Herein, a facile, low cost, and scalable method is provided for the fabrication of Mo2C‐based eletrocatalyst (Mo2C/G‐NCS) by a spray‐drying, and followed by annealing. As‐prepared Mo2C/G‐NCS electrocatalyst displays that ultrafine Mo2C nanopartilces are uniformly embedded into graphene wrapping N‐doped porous carbon microspheres derived from chitosan. Such designed structure offer several favorable features for hydrogen evolution application: 1) the ultrasmall size of Mo2C affords a large exposed active sites; 2) graphene‐wrapping ensures great electrical conductivity; 3) porous structure increases the electrolyte–electrode contact points and lowers the charge transfer resistance; 4) N‐dopant interacts with H+ better than C atoms and favorably modifies the electronic structures of adjacent Mo and C atoms. As a result, the Mo2C/G‐NCS demonstrates superior HER activity with a very low overpotential of 70 or 66 mV to achieve current density of 10 mA cm−2, small Tafel slope of 39 or 37 mV dec−1, respectively, in acidic and alkaline media, and high stability, indicating that it is a great potential candidate as HER electrocatalyst.

中文翻译:

碳化钼纳米颗粒涂覆到石墨烯包裹的氮掺杂多孔碳微球中,可在酸性和碱性介质中高效电催化析氢

碳化钼(Mo 2 C)被认为是析氢反应(HER)中贵金属的替代电催化剂。本文提供了一种简便、低成本且可扩展的方法,通过喷雾干燥和退火制备 Mo 2 C 基电催化剂(Mo 2 C/G-NCS)。所制备的Mo 2 C/G-NCS电催化剂显示,超细Mo 2 C纳米颗粒均匀地嵌入到包裹着源自壳聚糖的氮掺杂多孔碳微球的石墨烯中。这种设计的结构为析氢应用提供了几个有利的特征:1)Mo 2 C的超小尺寸提供了大的暴露活性位点;2)石墨烯包裹确保良好的导电性;3)多孔结构增加了电解质-电极接触点并降低了电荷转移电阻;4) N掺杂剂与H + 的相互作用比C原子更好,并且有利于改变相邻Mo和C原子的电子结构。因此,Mo 2 C/G-NCS 表现出优异的 HER 活性,具有 70 或 66 mV 的极低过电势,可分别实现 10 mA cm -2的电流密度、39 或 37 mV dec -1的小塔菲尔斜率,在酸性和碱性介质中,以及高稳定性,表明它是作为HER电催化剂的巨大潜力候选者。
更新日期:2018-01-03
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