二維WS_2-MoS_2異質結構於光催化產氫效率之研究

2D WS_2-MoS_2 heterostructures for photocatalytic hydrogen evolution

賴冠傑(Guan-Jie Lai) ； 呂明諺(Ming-Yen Lu)

《真空科技》 31卷1期 (2018/03) Pp. 21~1-21~8

摘要

低成本與高效率的光觸媒對光催化產氫的開發在工業的應用性是相當重要的。本研究中，我們設計了不包含貴重金屬的光觸媒，WS_2-MoS_2奈米複合材料。MoS_2與WS_2常被作為助催化劑幫助其他催化劑進行反應，但這兩個材料的結合有一些優點，因為相同的晶體結構且晶格常數相近，這意味著兩個材料之間晶格不匹配的程度很低，使得鍵結強度較高。此外，因為恰當的能帶分布可以有效的分離光致電子電洞對，進而提升產氫效能。但少層數的WS_2-MoS_2異質結構才能有效催化，為了得到少層數WS_2-MoS_2異質結構，將異質結構塊材置於酒精水溶液中，並以超音波震盪與離心處理，藉由挑選合適的酒精水溶液濃度，少層數WS_2-MoS_2異質結構可均勻的散佈在酒精水溶液中，也讓後續產氫反應中不需額外的攪拌。研究中以少層數WS_2-MoS_2異質結構為催化材料，沒有使用貴重金屬可大幅降低產氫光觸媒的成本，並提供設計光觸媒材料一個新的方式。

關鍵字

二維材料 ； 異質結構 ； 液相剝離法 ； 光觸媒 ； 水分解產氫

並列摘要

For industrial developments, the exploitation of materials for a low-cost and efficient photocatalytic hydrogen evolution is very crucial. Herein, we implemented the study to discuss the photocatalytic hydrogen evolution of the noble-metal-free WS_2-MoS_2 heterostructures. The MoS_2 and WS_2 are often used as co-catalysts with other materials. However, it is advantageous to combine these two together. MoS_2 and WS_2 are with the same crystal structure and have similar lattice parameters, which implies the small lattice mismatch between MoS_2 and WS_2. Moreover, due to the appropriate band-gap alignments between MoS_2 and WS_2, the charge separation under light illumination is remarkable, which enhances the hydrogen evolution performances. To ensure the few-layered structure for photocatalytic hydrogen evolution, the few-layered WS_2-MoS_2 heterostructures were acquired by using the ultrasonication and centrifugation in the ethanol aqueous solution. With the suitable concentration of ethanol aqueous solution, the few-layered WS_2-MoS_2 heterostructures were uniformly dispersed in ethanol aqueous solution. Hence, the few-layered WS_2-MoS_2 heterostructures reduce the need for external agitation during hydrogen production. We believe the noble-metal-free photocatalysts will largely reduce the cost and open up new prospects to design photocatalytic materials for efficient hydrogen production.

並列關鍵字

2D materials ； Heterostructure ； Liquid phase exfoliation ； Photocatalyst ； Water splitting ； Hydrogen evolution