Enhancement of the hydrogen evolution performance by finely tuning the morphology of Co-based catalyst without changing chemical composition
Enhancement of the hydrogen evolution performance by finely tuning the morphology of Co-based catalyst without changing chemical composition
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DOI：
10.1007/s12274-018-2201-y
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发表时间：
2019-01-01
期刊：
影响因子：
9.9
通讯作者：
Wang, Erkang
中科院分区：
文献类型：
--
作者：
Gu, Wenling;Hu, Liuyong;Wang, Erkang
过渡金属磷化物作为贵金属催化剂的有前景的替代品，已被广泛用作析氢反应（HER）的高效电催化剂。本工作通过改变水热条件合成了三种不同尺寸和纳米结构的钴-8-羟基喹啉(Coq(x))，根据尺寸的减小分别命名为Coq(x)-L、Coq(x)-M和Coq(x)-S。因此，通过Coq(x)的连续碳化和磷化获得了具有三种不同尺寸纳米结构(CoxP/NC-L、CoxP/NC-M和CoxP/NC-S)的CoxP/NC。 X射线衍射（XRD）和X射线光电子能谱（XPS）结果表明这些具有不同形貌的催化剂具有相同的化学组成。因此，进行系统研究以揭示具有相同化学成分的材料的催化性能与形貌之间的关系。实验结果表明CoxP/NC的形貌对表面积和电子转移起着至关重要的作用。最后，具有最小尺寸纳米结构的CoxP/NC-S催化剂在0.1 M HClO4和1.0 M KOH中表现出最佳的HER性能，在电流密度为10 mA/cm(2)（= 56.9和115.6 mV）时具有低过电势和小塔菲尔斜率（52.3和69.3 mV/dec）以及长期稳定性。
Transition-metal phosphides, as the promising alternatives to noble metal catalysts, have been widely used as efficient electrocatalysts for hydrogen evolution reaction (HER). In this work, three kinds of cobalt-8-hydroxyquinoline (Coq(x)) with different size and nanostructures are synthesized by varying the hydrothermal conditions, which was named as Coq(x)-L, Coq(x)-M and Coq(x)-S according to the decreased size. Accordingly, the CoxP/NC with three different size nanostructures (CoxP/NC-L, CoxP/NC-M and CoxP/NC-S) are obtained by the sequential carbonization and phosphidation of Coq(x). The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results imply the identical chemical composition in these catalysts with different morphologies. Thus, systematic study is carried out to reveal the relationship between catalytic performance and morphologies of materials with the same chemical composition. The experimental result indicates that the morphology of CoxP/NC plays a crucial role on the surface area and electron transfer. Finally, the catalyst of CoxP/NC-S with the smallest size nanostructrue exhibits the best HER performance with a low overpotential at current density of 10 mA/cm(2) ( = 56.9 and 115.6 mV) and a small Tafel slope (52.3 and 69.3 mV/dec) in both 0.1 M HClO4 and 1.0 M KOH as well as long-term stability.