Fu Cong, Liu Lingfang, Wang Yu, Wei Yaxiong, Huang Weixin, Zhao Guofeng
Key Laboratory of Functional Molecular Solids Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, P. R. China.
Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, School of Physics and Electronic Information, Anhui Normal University, Wuhu 241002, China.
ACS Appl Mater Interfaces. 2024 Oct 23;16(42):57927-57935. doi: 10.1021/acsami.4c14255. Epub 2024 Oct 15.
The Z-scheme heterojunction has been demonstrated to be effective in tuning the photocatalytic performance of photocatalysts. However, there is still a lack of quantitative and in-depth research on how the Z-scheme heterojunction affects the concentration of surface-reaching photoexcited charges. Here, by combining time-resolved spectroscopies and kinetic analysis, the concentration of surface-reaching photoholes () within g-CN/TiO Z-scheme heterojunctions was quantitatively analyzed for the first time. Quantitative measurements reveal that of the prepared Z-scheme photocatalysts is highly dependent on the g-CN content and the induced Z-scheme heterojunctions at the g-CN/TiO interface. Encouragingly, we found that a properly engineered Z-scheme heterojunction with close coupling of g-CN and TiO can significantly increase the , leading to nearly a 1.7-fold increase compared with pristine TiO samples. Furthermore, a distinct hole trap state-mediated Z-scheme charge transfer mechanism was uncovered in which the intrinsic interface defects at the g-CN/TiO junction act as hole traps, accelerating interface electron-hole recombination, thereby boosting spatial charge separation and ultimately enriching the . This work provides insights into understanding and controlling electron pathways and in Z-scheme photocatalysis, with implications for the screening of different types of direct Z-scheme photocatalysts.
Z 型异质结已被证明在调节光催化剂的光催化性能方面是有效的。然而，关于 Z 型异质结如何影响表面光激发电荷的浓度，仍然缺乏定量和深入的研究。在此，通过结合时间分辨光谱和动力学分析，首次对 g-CN/TiO Z 型异质结内到达表面的光生空穴（）浓度进行了定量分析。定量测量表明，所制备的 Z 型光催化剂的 高度依赖于 g-CN 含量以及 g-CN/TiO 界面处诱导的 Z 型异质结。令人鼓舞的是，我们发现 g-CN 和 TiO 紧密耦合的适当设计的 Z 型异质结可以显著增加 ，与原始 TiO 样品相比增加了近 1.7 倍。此外，还揭示了一种独特的空穴陷阱态介导的 Z 型电荷转移机制，其中 g-CN/TiO 结处的固有界面缺陷充当空穴陷阱，加速界面电子-空穴复合，从而促进空间电荷分离并最终富集 。这项工作为理解和控制 Z 型光催化中的电子路径和 提供了见解，对筛选不同类型的直接 Z 型光催化剂具有启示意义。
