Controlling the dendritic structure and the photo-electrocatalytic properties of highly crystalline MoS2 on sapphire substrate
Controlling the dendritic structure and the photo-electrocatalytic properties of highly crystalline MoS2 on sapphire substrate
复制标题
控制蓝宝石基底上高结晶MoS2的枝晶结构和光电催化性能
DOI：
10.1088/2053-1583/aacc90
复制
发表时间：
2018
期刊：
影响因子：
5.5
通讯作者：
Dou R. F.
中科院分区：
文献类型：
--
作者：
Ma J.;Li X. Y.;Gan L.;Zhang S. P.;Cao Y. F.;Nie Z. W.;Wang X. N.;Ma D. L.;He L.;Nie J. C.;Xiong C. M.;Dou R. F.
在蓝宝石 (0 0 0 1) 基底上可控地制造了具有树枝状形状的 2D 结晶 MoS 2 薄片，用于使用常压化学气相沉积 (CVD) 的析氢反应 (HER) 中的催化应用。与硫源相比，通过分别设定两种前驱体的温度并提前加热MoO 3 15分钟来控制所提出的生长过程。然后，在富硫条件下，获得了所需的树枝状MoS 2 单层薄片，并表现出三重对称特征。 MoS 2 枝晶的各个分支被区分为由沿特定晶体取向从角到底部顺序排列的微小三角形结构组成。进一步观察到从树枝状形态到紧凑三角形形态的形状演变强烈依赖于它们沿载气流位于基板上的区域。讨论了整个演化过程的机制与 CVD 生长参数的关系，例如硫与金属 (S/M) 通量比、硫的引入时间和基底对称性。通过精心调整生长条件，在蓝宝石衬底上获得了大尺寸MoS 2 枝晶单层薄片，并将其严格转移到Au箔上以检测光电催化性能。对由此得到的树枝状MoS 2 晶体片的光电催化HER和相同单位面积内具有不同畴边长的致密三角形结构进行了分析比较。高孔边缘暴露的MoS 2 枝晶在HER中降低的塔菲尔斜率和大的交换电流密度表明它们是一种有前途的HER催化剂。
2D crystalline MoS 2 flakes with the dendritic shape have been controllably fabricated on a sapphire (0 0 0 1) substrate for catalytic applications in the hydrogen evolution reaction (HER) using atmospheric pressure chemical vapor deposition (CVD). The proposed growth process was controlled by separately setting the temperature of two precursors and heating MoO 3 for 15 min in advance compared with the sulfur source. Then, under a sulfur-rich condition, the desired dendritic MoS 2 monolayer flakes were obtained and exhibited a threefold symmetric feature. The individual branch of MoS 2 dendrites was distinguished to be consisted of tiny triangular structures sequentially arranged by the corner to the bottom along the specific crystalline orientations. The shape evolution from the dendritic to the compact triangular morphology was further observed strongly depending on their regions located on the substrate along the carrier gas flow. The mechanism underlying the entire evolution process was discussed in relation to the CVD growth parameters, such as the sulfur-to-metal (S/M) flux ration, the introduction time of sulfur and the substrate symmetry. By carefully tailoring the growth condition, the large scale MoS 2 dendrites monolayer flakes were obtained on sapphire substrate, which was strictly transferred on the Au foil to detect the photo-electrocatalytic properties. The photo-electrocatalytic HER of the thus dendritic MoS 2 crystalline flakes and the compact triangular structures with different domain edge lengths in the same unit area were analytically compared. The lowered Tafel slope and the large exchange current density of the high-porous edge-exposed MoS 2 dendrites in HER demonstrated that they are a promising HER catalyst.