Abstract In this work, a hierarchical porous SnS2/rGO/TiO2 hollow sphere heterojunction that allows highly-efficient light utilization and shortening distance of charge transformation is rationally designed and synthesized. More importantly, an rGO interlayer is successfully embedded between the TiO2 hollow sphere shells and outermost SnS2 nanosheets. This interlayer functions as a bridge to connect the two light-harvesting semiconductors and acts as a hole injection layer in the tandem heterojunction. The induced built-in electric fields on both sides of the interface precisely regulate the spatial separation and directional migration of the photo-generated holes from the light-harvesting semiconductor to the rGO hole injection interlayer. These synergistic effects greatly prolong the lifetime of the photo-induced charge carriers. The optimized tandem heterojunction with a 2 wt% rGO loading demonstrate enhanced visible-light-driven photocatalytic activity for Rhodamine B (RhB) dye degradation (removal rate: 97.3%) and Cr(VI) reduction (removal rate: 97.09%). This work reveals a new strategy for the rational design and assembly of hollow-structured photocatalytic materials with spatially separated reduction and oxidation surfaces to achieve excellent photocatalytic performance.

中文翻译：

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通过源自功函数差异的内置界面电场加速定向电荷分离

摘要 在这项工作中，我们合理设计和合成了一种具有高效光利用和缩短电荷转换距离的分级多孔SnS2/rGO/TiO2空心球异质结。更重要的是，rGO 夹层成功嵌入在 TiO2 空心球壳和最外层的 SnS2 纳米片之间。该夹层充当连接两个光捕获半导体的桥梁，并充当串联异质结中的空穴注入层。界面两侧的感应内置电场精确地调节了光生空穴从集光半导体到 rGO 空穴注入夹层的空间分离和定向迁移。这些协同效应大大延长了光生电荷载流子的寿命。具有 2 wt% rGO 负载的优化串联异质结表现出增强的可见光驱动的罗丹明 B (RhB) 染料降解（去除率：97.3%）和 Cr（VI）还原（去除率：97.09%）的光催化活性。这项工作揭示了一种合理设计和组装具有空间分离的还原和氧化表面的中空结构光催化材料以实现优异光催化性能的新策略。