An unexpected interaction between a H2O2 molecule and anatase TiO2(101) surface

Abstract In this paper, the interactions between a H 2 O 2 molecule and anatase TiO 2 (101) (A-TiO 2 ) surface are studied by first-principle calculations. It is found that a H 2 O 2 molecular can adsorb or dissociate on A-TiO 2 (101) surface, in agreement with previous results. When a H 2 O 2 molecule dissociates, Ti-μ-peroxide configurations may form. It should be noticed that a more stable Ti-μ-peroxide configuration is found in this paper. More interestingly, an oxygen atom of this dissociated H 2 O 2 can enter into A-TiO 2 (101) lattice, i.e. , forming surface (O 2 )o. The energy barriers for formations of new Ti-μ-peroxide and surface (O 2 )o species are 0.30 and 1.28 eV, respectively, which explain previous experimental results that the formations of Ti-μ-peroxide and (O 2 )o species are under lower and higher temperatures, respectively. The localized gap state of Ti-μ-peroxide disappears after the formation of surface (O 2 )o, and thus the recombination probability of electron-hole pairs should be reduced for the O-rich A-TiO 2 . These results can rationalize experimental results that the photocatalytic activity of A-TiO 2 sample can be changed by H 2 O 2 treating under different temperature.