A DFT + U study of (Rh, Nb)-codoped rutile TiO2.
A systematic study of electronic structure and band gap states is  conducted to analyze the monodoping and charge compensated codoping of rutile TiO(2) with Rh and Nb, using the DFT + U approach. Doping of rutile TiO(2) with Rh atoms induces hybridized O 2p and Rh 4d band gap states leading to a red shift of the optical absorption edge, consistent with previous experimental studies. Since Rh monodoping may induce recombination centers, charge compensated codoping with Rh and Nb is also explored. This codoping induces an electron transfer from Nb induced states to Rh 4d states, which suppresses the formation of Rh(4+), thereby leading to a reduction in recombination centers and to the formation of more stable Rh(3+). A combination of band gap reduction by 0.5 eV and the elimination of band gap states that account for recombination centers makes (Rh, Nb)-codoped TiO(2) a more efficient and stable photocatalyst.
Department of Materials Science and Engineering, University of Toronto, 184 College Street, Suite 140, Toronto, ON M5S 3E4, Canada.
Kulbir Kaur
KK
Ghuman
Chandra Veer
CV
Singh
D003198:Computer Simulation; D008958:Models, Molecular; D015394:Molecular Structure; D009556:Niobium / Q000737:chemistry*; D011789:Quantum Theory; D012238:Rhodium / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
D009556:Niobium; C009495:titanium dioxide; D014025:Titanium; D012238:Rhodium