Molybdenum Ditelluride Rendered into an Efficient and Stable Electrocatalyst for the Hydrogen Evolution Reaction by Polymorphic Control
Molybdenum Ditelluride Rendered into an Efficient and Stable Electrocatalyst for the Hydrogen Evolution Reaction by Polymorphic Control
复制标题
DOI：
10.1002/ente.201700489
复制
发表时间：
2018-02-01
影响因子：
3.8
通讯作者：
Ganin, Alexey Y.
中科院分区：
文献类型：
--
作者：
McGlynn, Jessica C.;Cascallana-Matias, Irene;Ganin, Alexey Y.
电催化析氢反应（HER）对于从可持续来源生产H-2至关重要。目前，铂是这种转变的最佳电催化剂，但其他基于不那么珍贵的元素的材料现在正引起越来越多的关注。在这些替代品中，硫族钼表现出特别的前景。MoS2在这方面已经得到了广泛的研究，这突出了多态性对催化活性的重要作用。然而，转化为活性多晶体是复杂的，并且催化剂在电化学条件下的稳定性较差。相比之下，MoTe2作为HER的电催化剂的研究很少。本文中，我们使用一种简单的固态途径分离出MoTe2的半导体和金属多晶，并表明通过简单的温度退火协议可以在不改变形貌的情况下实现MoTe2的两种多晶之间的相互转换。虽然半导体形式是一种相当差的电催化剂，但金属1T-MoTe2多晶型是一种高效和稳定的电催化剂。即使在散装形式下，它也实现了低过电位，Tafel斜率为（78 +/- 4）mV dec（-1）和完全的法拉第效率。这些发现强调了多晶控制在HER催化剂开发中的重要性，并为发现新的和改进的电催化剂提供了一条有效的途径。
The electrocatalytic hydrogen evolution reaction (HER) is of central importance for the production of H-2 from sustainable sources. Currently, Pt is the best electrocatalyst for this transformation, but other materials based on less-precious elements are now attracting increased attention. Of these alternatives, the molybdenum chalcogenides show particular promise. MoS2 has been explored extensively in this regard, which has highlighted the important role of polymorphism for catalytic activity. However, the conversion into an active polymorph is complex, and the stability of the catalyst under electrochemical conditions is poor. In contrast, MoTe2 has been barely studied as an electrocatalyst for the HER. Herein, we isolate the semiconducting and metallic polymorphs of MoTe2 using an easy solid-state route and show that interconversion between the two polymorphs of MoTe2 can be achieved without a change in morphology by a simple temperature-annealing protocol. Although the semiconducting form is a rather poor electrocatalyst for the HER, the metallic 1T-MoTe2 polymorph is an efficient and stable electrocatalyst for the HER in 1 m H2SO4. Even in the bulk form, it achieved a low overpotential with a Tafel slope of (78 +/- 4) mV dec(-1) and full Faradaic efficiency. These findings highlight the importance of polymorphic control in the development of HER catalysts and suggest an efficient route for the discovery of new and improved electrocatalysts.