Interfacial Interactions of Semiconductor with Graphene and Reduced Graphene Oxide: CeO₂ as a Case Study

Abstract

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.

Origin of enhanced visible-light photocatalytic activity of transition-metal (Fe, Cr and Co)-doped CeO2: effect of 3d orbital splitting

“…S3 (a1) and (a2). The position and width of the Ce 4f and O 2p bands are in good agreement with the experiment and previous calculations [42,58,59]. Here, the calculated band structure, electron density distributions, DOS and PDOS of FeCe-CeO2 are displayed in Fig.…”

Recent Progress in the Development of Semiconductor‐Based Photocatalyst Materials for Applications in Photocatalytic Water Splitting and Degradation of Pollutants

“…First‐principles study has been the most promising tool to address the interfacial interaction, which is a contributing factor to photocatalysis. The electronic structure and interfacial charge transfer in hybrid CeO 2 /GR(rGO) nanocomposites have been investigated within DFT/LDA + U method with PAW approach . LDA functional implemented was due to the long‐range van der Waals interaction, which was anticipated to be significant in this system.…”

Enhanced Microwave Absorption Properties of CeO2 Nanoparticles Supported on Reduced Graphene Oxide

“…16,[24][25][26] Therefore, recent studies focus on RGO/CeO 2 nanocomposites, in which Ce 4þ localized on crystal lattice can be partly reduced to Ce 3þ with the aid of RGO and exhibits enhanced electrical conductivity. [27][28][29][30] Moreover, using graphene/RGO as the template, the nanoparticles can act as an anchor, and their dispersion can be enhanced. Owing to the ability of the cerium atom to easily and drastically adjust its electronic con¯guration to best¯t its immediate environment, 22 the charge transfer between RGO sheets and CeO 2 nanoparticles leads to the increase of Ce 3þ concentration and is accompanied with rich oxygen vacancies.…”