A DFT + U study of (Rh, Nb)-codoped rutile TiO2
Kulbir Kaur Ghuman1, Chandra Veer Singh
1Department of Materials Science and Engineering, University of Toronto, 184 College Street, Suite 140, Toronto, ON M5S 3E4, Canada.
Summary
Rh and Nb codoping of titanium dioxide (TiO2) enhances its efficiency and stability as a photocatalyst by reducing recombination centers and narrowing the band gap. This engineered material shows promise for improved solar energy applications.
Area of Science:
- Materials Science
- Solid State Physics
- Photocatalysis
Background:
- Rutile titanium dioxide (TiO2) is a widely studied photocatalyst.
- Monodoping with certain elements can introduce desirable electronic properties but may also create recombination centers.
- Understanding the electronic structure and band gap states is crucial for optimizing photocatalyst performance.
Purpose of the Study:
- To investigate the electronic structure and band gap states of rutile TiO2 doped with Rhodium (Rh) and Niobium (Nb).
- To analyze the effects of monodoping versus charge-compensated codoping on TiO2.
- To evaluate the potential of (Rh, Nb)-codoped TiO2 as an improved photocatalyst.
Main Methods:
- Density Functional Theory (DFT) with the DFT + U approach was employed.
- Systematic study of electronic structure and band gap states.
- Analysis of doping effects on optical absorption and charge transfer.
Main Results:
- Rh monodoping in TiO2 creates hybridized O 2p and Rh 4d band gap states, causing a red shift in optical absorption.
- Codoping with Rh and Nb suppresses the formation of Rh(4+) by facilitating electron transfer from Nb to Rh states.
- This codoping reduces recombination centers and stabilizes Rh in the Rh(3+) state.
Conclusions:
- The band gap of TiO2 is reduced by 0.5 eV through (Rh, Nb)-codoping.
- Elimination of recombination centers and band gap narrowing significantly enhance photocatalyst efficiency and stability.
- (Rh, Nb)-codoped TiO2 presents a promising material for advanced photocatalytic applications.
