Single-Step Chemical Vapor Deposition Growth of Platinum Nanocrystal: Monolayer MoS2 Dendrite Hybrid Materials for Efficient Electrocatalysis,Chemistry of Materials

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Single-Step Chemical Vapor Deposition Growth of Platinum Nanocrystal: Monolayer MoS2 Dendrite Hybrid Materials for Efficient Electrocatalysis
Chemistry of Materials ( IF 7.2 ) Pub Date : 2020-09-21 , DOI: 10.1021/acs.chemmater.0c01923
Wenshuo Xu _{1,

2} , Sha Li ₁ , Gyeong Hee Ryu ₁ , Peng Tang ₁ , Mauro Pasta _{1,

2} , Jamie H. Warner _{3,

4,

5}

Affiliation

Two-dimensional (2D) molybdenum disulfide (MoS₂) has excellent electrocatalytic behavior for the hydrogen evolution reaction (HER), where the catalysis of 2H phase originates from its edges, defects, and strains. Most synthetic methods to activate the electrochemically inert basal planes with catalytic active metals are completed by sequential steps. However, this is extremely time-consuming and lacks production scalability. Herein, we develop a one-step strategy to achieve efficient electrocatalyst of Pt:MoS₂ hybrid utilizing atmospheric pressure chemical vapor deposition synthesis on a conductive glassy carbon (GC) plate that can be directly employed as the working electrode in the HER. The monolayer thickness ensures decreased interlayer electron hopping and increased efficiency of the charge transfer from the electrode. We tune the domain morphology by controlling the precursor flux to enter kinetic or thermodynamic growth regime, delivering dendritic or triangular shape. The materials chemistry undertaken provides fundamental insights into the instability of Pt as metal substitutional dopants in the MoS₂ lattice, and instead the stable configuration observed is with Pt as highly dispersed small nanocrystals and single atoms bound to the MoS₂ surface. The Pt functionalization at a reduced loading level modulates the favorable HER pathway and triggers synergies in the cocatalyst, which exhibits an onset potential of 48 mV, a Tafel slope of 46 mV dec^–1, and an exchange current density of 110 μA cm^–2. The enriched edges and defects of dendrite endow it superiority to the triangle, with regard to the density of catalytic sites and synergistic effects along with electrical resistance. These underpin the positive role of a large dendritic MoS₂ monolayer as a Pt scaffold in water electrolysis.

中文翻译：

铂纳米晶体的一步化学气相沉积生长：高效电催化的单层MoS ₂树突杂化材料

二维（2D）二硫化钼（MoS ₂）对氢气析出反应（HER）具有出色的电催化性能，其中2H相的催化作用源自其边缘，缺陷和应变。大多数用催化活性金属活化电化学惰性基面的合成方法都是通过连续步骤完成的。但是，这非常耗时并且缺乏生产可伸缩性。本文中，我们开发了一种实现Pt：MoS ₂高效电催化剂的一步策略。混合技术，利用常压化学气相沉积法在可直接用作HER中工作电极的导电玻璃碳（GC）板上进行合成。单层厚度确保减少的层间电子跳跃和增加的从电极的电荷转移效率。我们通过控制前体通量进入动力学或热力学生长机制，传递树状或三角形形状来调整域形态。进行的材料化学研究为Pt在MoS ₂晶格中作为金属替代掺杂剂的不稳定性提供了基本的见识，相反，观察到的稳定构型是Pt作为高度分散的小纳米晶体和与MoS ₂结合的单原子表面。负载水平降低时的Pt功能化调节了有利的HER途径并触发了助催化剂的协同作用，该助催化剂的起始电位为48 mV，Tafel斜率为dec ^–1的Tafel斜率，交换电流密度为110μAcm ^–2。就催化部位的密度和协同效应以及电阻而言，枝晶的丰富边缘和缺陷使其具有优于三角形的优势。这些加强了大树状MoS ₂单层作为Pt支架在水电解中的积极作用。

更新日期：2020-10-13

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