SnS2/Na0.9Mg0.45Ti3.55O8 (SNMTO) composite photocatalyst was synthesized by a hydrothermal method. The chemical combination in lattice scale between SnS2 and Na0.9Mg0.45Ti3.55O8 (NMTO) was observed by high-resolution transmission electron microscopy, indicating that heterojunctions were obtained between SnS2 and NMTO. The photocatalytic activity of SNMTO heterojunctions was improved in comparison with that of pure NMTO and SnS2 for the photocatalytic degradation of methylene blue and Rhodamine B. Electrons were excited in n-type semiconductors NMTO and SnS2 under light illumination, and a part of them moved to the interface, determined with the surface potential reduction observed directly by Kelvin probe force microscopy. The charge redistribution in the composite illustrates a high density of interface states between SnS2 and NMTO, which attract lots of photoelectrons, as a result enhancing the photocatalytic performance. This finding is very different from the speculation that the photogenerated electrons and holes migrate from one part to another because it is difficult for charge carriers to travel through the interface with high energy.

中文翻译：

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光催化过程中 SnS2/Na0.9Mg0.45Ti3.55O8 异质结中的电荷转移

采用水热法合成了SnS2/Na0.9Mg0.45Ti3.55O8(SNMTO)复合光催化剂。高分辨透射电子显微镜观察到SnS2和Na0.9Mg0.45Ti3.55O8(NMTO)在晶格尺度上的化学结合，表明SnS2和NMTO之间形成了异质结。与纯 NMTO 和 SnS2 相比，SNMTO 异质结的光催化降解亚甲基蓝和罗丹明 B 的光催化活性有所提高。在光照下，n 型半导体 NMTO 和 SnS2 中的电子被激发，其中一部分转移到界面，由开尔文探针力显微镜直接观察到的表面电位降低确定。复合材料中的电荷重新分布说明了 SnS2 和 NMTO 之间的高密度界面态，吸引大量光电子，从而提高光催化性能。这一发现与光生电子和空穴从一个部分迁移到另一个部分的推测非常不同，因为电荷载流子很难以高能量穿过界面。