Centre for Composite Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China.
Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin, 150040, China.
Adv Mater. 2017 Jul;29(28). doi: 10.1002/adma.201700311. Epub 2017 May 19.
MoSe is a promising earth-abundant electrocatalyst for the hydrogen-evolution reaction (HER), even though it has received much less attention among the layered dichalcogenide (MX ) materials than MoS so far. Here, a novel hydrothermal-synthesis strategy is presented to achieve simultaneous and synergistic modulation of crystal phase and disorder in partially crystallized 1T-MoSe nanosheets to dramatically enhance their HER catalytic activity. Careful structural characterization and defect characterization using positron annihilation lifetime spectroscopy correlated with electrochemical measurements show that the formation of the 1T phase under a large excess of the NaBH reductant during synthesis can effectively improve the intrinsic activity and conductivity, and the disordered structure from a lower reaction temperature can provide abundant unsaturated defects as active sites. Such synergistic effects lead to superior HER catalytic activity with an overpotential of 152 mV versus reversible hydrogen electrode (RHE) for the electrocatalytic current density of j = -10 mA cm , and a Tafel slope of 52 mV dec . This work paves a new pathway for improving the catalytic activity of MoSe and generally MX -based electrocatalysts via a synergistic modulation strategy.
MoSe 是一种很有前途的富地球元素电催化剂，用于析氢反应（HER），尽管与迄今为止层状二硫化物（MX ）材料中的 MoS 相比，它受到的关注要少得多。在这里，提出了一种新的水热合成策略，以实现部分结晶 1T-MoSe 纳米片的晶体相和无序度的同时协同调制，从而显著提高其 HER 催化活性。使用正电子湮没寿命谱结合电化学测量进行的仔细结构表征和缺陷表征表明，在合成过程中使用大量过量的 NaBH 还原剂形成 1T 相可以有效地提高本征活性和导电性，而低温下的无序结构可以提供丰富的不饱和缺陷作为活性位点。这种协同效应导致 HER 催化活性优异，相对于可逆氢电极（RHE）的电催化电流密度 j = -10 mA cm 时的过电势为 152 mV，塔菲尔斜率为 52 mV dec 。这项工作为通过协同调制策略提高 MoSe 和一般 MX 基电催化剂的催化活性开辟了新途径。
