Interfacial interactions of semiconductor with graphene and reduced graphene oxide: CeO2 as a case study.
Interfacial interactions of semiconductor with graphene and reduced graphene oxide: CeO2 as a case study.
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DOI：
10.1021/am5058772
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发表时间：
2014-10
影响因子：
9.5
通讯作者：
Liang Xu;Wei‐Qing Huang;Lingling Wang;Gui‐Fang Huang
中科院分区：
文献类型：
--
作者：
Liang Xu;Wei‐Qing Huang;Lingling Wang;Gui‐Fang Huang
对光收集系统的卓越构建块的追求刺激了越来越多的努力来开发用于太阳能电池和光催化剂的石墨烯（GR）基半导体复合材料。GR基复合材料的一个关键问题是理解其组分之间的相互作用，这是一个在密集的实验研究之后仍未解决的问题。在这里，我们使用二氧化铈（CeO 2）作为模型半导体系统地探索半导体与GR和还原氧化石墨烯（RGO）的相互作用与大规模从头计算。在界面处转移的电荷量随着O原子浓度的增加而增加，表明CeO 2与RGO之间的相互作用比CeO 2与GR之间的相互作用强得多，这是由于界面之间的平均平衡距离减小。半导体和RGO之间的较强的相互作用，预计是普遍的，证明了两个范例的TiO 2和Ag 3 PO 4与RGO耦合的结果。CeO 2（111）/GR界面为I型异质结，而CeO 2（111）表面与RGO之间为II型交错能带排列。CeO 2/RGO复合材料的光催化活性增强主要是由于其禁带宽度减小、具有II型异质结以及RGO表面的氧原子带负电荷。这些发现可以合理化现有的实验报告，并丰富我们的理解GR基复合材料的相互作用，开发高性能的光催化剂和太阳能电池。
The pursuit of superb building blocks of light harvesting systems has stimulated increasing efforts to develop graphene (GR)-based semiconductor composites for solar cells and photocatalysts. One critical issue for GR-based composites is understanding the interaction between their components, a problem that remains unresolved after intense experimental investigation. Here, we use cerium dioxide (CeO2) as a model semiconductor to systematically explore the interaction of semiconductor with GR and reduced graphene oxide (RGO) with large-scale ab initio calculations. The amount of charge transferred at the interfaces increases with the concentration of O atoms, demonstrating that the interaction between CeO2 and RGO is much stronger than that between CeO2 and GR due to the decrease of the average equilibrium distance between the interfaces. The stronger interaction between semiconductor and RGO is expected to be general, as evidenced by the results of two paradigms of TiO2 and Ag3PO4 coupled with RGO. The interfacial interaction can tune the band structure: the CeO2(111)/GR interface is a type-I heterojunction, while a type-II staggered band alignment exists between the CeO2(111) surface and RGO. The smaller band gap, type-II heterojunction, and negatively charged O atoms on the RGO as active sites are responsible for the enhanced photoactivity of CeO2/RGO composite. These findings can rationalize the available experimental reports and enrich our understanding of the interaction of GR-based composites for developing high-performance photocatalysts and solar cells.