In the hydrogen production procedure,anatase TiO2 has been used for splitting water to produce hydrogen.However,the reaction can not be driven by the visible light because of its wide energy band gap.First principle was used to study the electronic structures,optical properties,and band energy positions of Au-X (X=F,Cl,Br,I) co-doped anatase TiO2.The results revealed that the structures of Au-X (X=F,Cl,Br,I) co-doped anatase TiO2 were stable because of the negative binding energies.Co-doping can significantly reduce the band gap of TiO2,and introduced a hybrid energy level into the forbidden band,which was beneficial to visible light absorption and prevention of photo-generated carrier recombination.Au-F,Au-Cl and Au-Br co-doped systems satisfied the conditions of photocatalytic hydrolysis to produce hydrogen.
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