光电流
三元运算
材料科学
纳米复合材料
异质结
光致发光
光催化
化学工程
剥脱关节
碳纳米管
带隙
纳米技术
光电子学
催化作用
化学
有机化学
石墨烯
工程类
程序设计语言
计算机科学
作者
Wan-Kuen Jo,N. Clament Sagaya Selvam
标识
DOI:10.1016/j.apcata.2016.06.036
摘要
This article reports the synthesis and photocatalytic H2-generation of pristine and CdS-based hybrid photocatalysts. Acid-treated-multi-walled carbon nanotubes (a-MWCNTs) and colloids of the exfoliated two-dimensional MoS2 nanosheets were used for the preparation of binary CdS/a-MWCNTs and ternary CdS/MoS2/a-MWCNTs nanocomposites. Controlled exfoliation of as-synthesized bulk marigold flower-like MoS2 to few-layer MoS2 nanosheets shows a strong absorption and photoluminescence, indicating an indirect to direct bandgap transition. The visible-light photocatalytic H2-evolution performance of the ternary nanocomposites was superior to that of the binary and pure photocatalysts. Transient photocurrent results revealed that the ternary nanocomposite exhibits a maximum photocurrent density of 11.12 mA/cm2, which is 12 times higher than that of pristine CdS. This enhanced H2-generation performance and photocurrent response is attributed to the CdS/MoS2 heterojunction, which increases charge-separation efficiency of the composite. Furthermore, the presence of a-MWCNTs, as a co-catalyst/support, accounts for this excellent performance involving electron transfer from photoexcited CdS to MoS2 edges through a-MWCNTs; this transfer results in enhanced charge separation. This enhanced charge-separation efficiency and photostability was demonstrated using a suitable mechanism, which was evident from photocurrent measurements and photoluminescence data. In such ternary hybrids, metal co-catalysts showed H2-evolution activity with the following order: Pd > Ni > Au > Ag > Cu. This work further highlights the role of MoS2/CNTs p-n junction embedded in CdS which serves as a promising heterojunction that promoted hydrogen production.
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