Edge-Enriched 2D MoS2 Thin Films Grown by Chemical Vapor Deposition for Enhanced Catalytic Performance

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• 作者：Sha Li ; Shanshan WangMatteo M. Salamone ; Alex W. Robertson ; Simantini Nayak ; Heeyeon Kim ; S. C. Edman Tsang ; Mauro PastaJamie H. Warner
• 刊名：ACS Catalysis
• 出版年：2017
• 出版时间：January 6, 2017
• 年：2017
• 卷：7
• 期：1
• 页码：877-886
• 全文大小：788K
• ISSN：2155-5435

文摘

Chemical vapor deposition (CVD) is used to grow thin films of 2D MoS₂ with nanostructure for catalytic applications in the hydrogen evolution reaction (HER). Tailoring of the CVD parameters results in an optimized MoS₂ structure for the HER that consists of large MoS₂ platelets with smaller layered MoS₂ sheets growing off it in a perpendicular direction, which increases the total number of edge sites within a given geometric area. A surface area to geometric area ratio of up to ∼340 is achieved, benefiting from the edge-exposed high-porosity network structure. The optimized thickness of the MoS₂ film is determined for maximum performance, revealing that increasing thickness leads to increased impedance of the MoS₂ film and reduced current density. The current density of the optimum sample reaches as high as 60 mA/cm²_geo (normalized by geometric area) at an overpotential of 0.64 V vs RHE (in 0.5 M H₂SO₄), with a corresponding Tafel slope of ∼90 mV/dec and exchange current density of 23 μA/cm²_geo. The lowered Tafel slope and large exchange current density demonstrate that the high-porosity edge-exposed MoS₂ network structure is promising as a HER catalyst.