The interactions between TiO2 and graphene with surface inhomogeneity determined using density functional theory

Area of Science:

• Materials Science
• Nanotechnology
• Computational Chemistry

Background:

• Titanium dioxide (TiO2) and graphene composites are promising for photocatalysis due to enhanced electronic properties.
• Understanding the interface between TiO2 and graphene is crucial for optimizing composite performance.
• Graphene's surface modifications, including defects and functional groups, can influence material interactions.

Purpose of the Study:

• To model and investigate TiO2/graphene interfaces with various graphene surface modifications.
• To understand the impact of defects and functional groups on TiO2 binding and charge transfer.
• To assess the stability, structure, and potential photoactivity of modified TiO2/graphene systems.

Main Methods:

• Density Functional Theory (DFT) modeling was employed to simulate TiO2/graphene interfaces.
• Simulations included graphene with C vacancies, epoxide, and hydroxyl groups interacting with TiO2 clusters (3-45 atoms).
• Analysis focused on binding energies, charge transfer, and electronic structure (density of states).

Main Results:

• Pristine graphene shows weak van der Waals binding with TiO2.
• Carbon vacancies and epoxide groups on graphene significantly strengthen TiO2 binding, acting as anchoring sites.
• Hydroxyl groups lead to OH transfer and weak interactions, while charge transfer direction depends on graphene surface state.

Conclusions:

• Graphene surface defects and functional groups critically influence the stability and structure of TiO2/graphene interfaces.
• Engineered defects and functional groups can enhance TiO2 anchoring and facilitate charge transfer, boosting photocatalytic potential.
• This study provides insights into designing advanced TiO2/graphene photocatalysts by controlling graphene surface chemistry.