Coordination polymer structure and revisited hydrogen evolution catalytic mechanism for amorphous molybdenum sulfide.
Coordination polymer structure and revisited hydrogen evolution catalytic mechanism for amorphous molybdenum sulfide.
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DOI：
10.1038/nmat4588
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发表时间：
2016-06
期刊：
影响因子：
41.2
通讯作者：
Artero V
中科院分区：
文献类型：
--
作者：
Tran PD;Tran TV;Orio M;Torelli S;Truong QD;Nayuki K;Sasaki Y;Chiam SY;Yi R;Honma I;Barber J;Artero V
在水析氢反应中，硫化钼是极具吸引力的无贵金属电催化剂。结晶二硫化钼（c-MoS2）的原子结构和催化活性位点已经很好地确定，但非晶硫化钼（a-MoSx）的原子结构和催化活性位点尚未确定，而非晶硫化钼（a-MoSx）的HER活性明显高于其晶体对应物。在这里，我们证明了her活性的a- mosx，无论是作为纳米颗粒还是作为薄膜制备，都是一种由离散的[Mo3S13]2 -组成的分子基配位聚合物。在这些簇中的三个末端二硫化物（S22 -）配体中，两个是共享的以形成聚合物链。第三个游离体在析氢条件下生成氢化钼基团作为活性位点。因此，这种分子结构为重新审视a- mosx的催化活性机制以及解释其一些特殊性质（如还原活化和腐蚀）提供了基础。我们的发现为合理优化这种HER电催化剂作为铂的替代品开辟了新的途径。
Molybdenum sulfides are very attractive noble-metal free electrocatalysts for the hydrogen evolution reaction (HER) from water. Atomic structure and identity of the catalytically active sites have been well established for crystalline molybdenum disulfide (c-MoS2) but not for amorphous molybdenum sulfide (a-MoSx) which displays significantly higher HER activity compared to its crystalline counterpart. Here we show that HER–active a-MoSx, prepared either as nanoparticles or as films, is a molecular–based coordination polymer consisting of discrete [Mo3S13]2– building blocks. Of the three terminal disulfide (S22–) ligands within these clusters, two are shared to form the polymer chain. The third one remains free and generates molybdenum hydride moieties as the active site under H2 evolution conditions. Such a molecular structure therefore provides a basis for revisiting the mechanism of a-MoSx catalytic activity, as well as explaining some of its special properties such as reductive activation and corrosion. Our findings open up new avenues for the rational optimisation of this HER electrocatalyst as an alternative to platinum.