异质结
材料科学
三元运算
带隙
可见光谱
Boosting(机器学习)
载流子
电荷(物理)
光电子学
物理
机器学习
量子力学
计算机科学
程序设计语言
作者
Mingyue Zhu,Qian Liu,Wei Chen,Yuanyuan Yin,Lan Ge,Henan Li,Kun Wang
标识
DOI:10.1021/acsami.7b14412
摘要
The efficient separation of photogenerated electron-hole pairs in photoactive materials is highly desired, allowing their transfer to specific sites for undergoing redox reaction in various applications. The construction of ternary heterojunctions is a practical strategy to enhance the migration of photogenerated electron that realizes the synergistic effect of multicomponents rather than the simple overlay of single component. Here, we demonstrate an available way to fabricate new BiOCl/BiVO4/nitrogen-doped graphene quantum dot (N-GQD) ternary heterojunctions that exhibit higher efficiency in charge separation than any binary heterojunction or pure material under visible-light irradiation. UV-vis diffuse reflectance spectroscopy demonstrated that the proposed BiOCl/BiVO4/N-GQD ternary heterojunctions possess the narrower band gap energy. More importantly, the ternary heterojunctions reveal the prolonged lifetime of photogenerated charges and enhanced the separation efficiency of photogenerated electron-hole pairs, which may be ascribed to sensitization based on an internal Z-scheme charge transfer at the interface of N-GQDs with oxygen functional groups. Furthermore, we examine the photoactive performance of proposed ternary heterojunctions in aqueous solution by using the photodegradation of bisphenol A as a model system and BiOCl/BiVO4/N-GQD ternary heterojunctions also display a dramatically enhanced photodegradation rate. The proposed charge separation and transfer process of BiOCl/BiVO4/N-GQD ternary heterojunctions for the enhanced photoactivity were deduced by electrochemical measurements, photoluminescence, and electron spin resonance. The results demonstrate that a Z-scheme charge process was formed between BiOCl/BiVO4 binary heterojunctions and N-GQDs, leading to an efficient charge carrier separation and strong photocatalytic ability. Notably, this work may assist in a better understanding of the role of N-GQDs in kinds of heterojunctions. Conceivably, it can be extended to fabricate other photocatalytic systems and photoelectrochemical platforms associated with photoactive materials.
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