液相剝離法二硫化鎢－二硫化鉬之二維異質結構於提升光催化產氫之探討

Improved photocatalytic H_2 production of 2D WS_2-MoS_2 heterostructures via liquid phase exfoliation

李冠祺(Guan-Chi Lee) ； 賴冠傑(Guan-Jie Lai) ； 呂明諺(Ming-Yen Lu)

《真空科技》 33卷1期 (2020/03) Pp. 12~1-12~10

摘要

本研究中，我們成功以水熱法合成塊材的WS_2-MoS_2異質結構，接下來以液相剝離法製備出少層數的WS_2-MoS_2異質結構。首先，利用穿透式電子顯微鏡以及掃描穿透式電子顯微鏡分析塊材WS_2-MoS_2的異質結構。接著，以拉曼光譜儀確定WS_2及MoS_2共存。後續光催化產氫成果顯示，未經LPE處理之2% MoS_2塊材異質結構效率為7.5 μmol．h^(-1)．g^(-1)，而經LPE處理之異質結構效率則達92.3 mmol．h^(-1)．g^(-1)，相距極大。此外亦發現若少層數WS_2-MoS_2異質結構含有2 %重量組成的MoS_2，其催化能力最佳，分別為純材料WS_2和MoS_2的2.34倍和7.64倍，顯示異質結構中有較多的光致載子參與反應，達到良好的催化效果。此增益效果主要可歸因於適合的能帶匹配關係以及在可見光波段有額外的吸收峰值出現。

關鍵字

過渡金屬二硫族化合物 ； 異質結構 ； 液相剝離法 ； 光催化產氫

並列摘要

In this study, few-layered WS_2-MoS_2 heterostructures were fabricated through hydrothermal and liquid-phase exfoliation (LPE) method. First, the hetero-structures of bulk MoS_2-WS_2 were analyzed by TEM and STEM. Moreover, the coexistence of WS_2 and MoS_2 is confirmed by raman spectroscopy. The photocatalytic H_2 production analysis showed that the efficiency of untreated bulk heterostructures with 2 % of MoS_2 is 7.5 μmol．h^(-1)．g^(-1) and the efficiency of LPE treated heterostructures is 92.3 mmol．h^(-1)．g^(-1). In addition, we found that the few-layered WS_2-MoS_2 heterostructures with 2 w.t.%MoS_2 has the best efficiency which is 2.34, 7.64 times of pure WS_2 and MoS_2 respectively. It shows that more photoinduced carriers join the reaction in heterostructures and it enhances the catalytic efficiency. This enhancement is contributed to the appropriate bandgap alignments and the additional absorbance in visible light region.

並列關鍵字

Transition Metal Dichalcogenides ； Heterostructure ； Liquid Phase Exfoliation ； Photocatalytic Hydrogen Evolution