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Anticorrelation between Surface and Subsurface Point Defects and the Impact on the Redox Chemistry of TiO 2 (110)
Author(s) -
Yoon Yeohoon,
Du Yingge,
Garcia Juan C.,
Zhu Zihua,
Wang ZhiTao,
Petrik Nikolay G.,
Kimmel Gregory A.,
Dohnalek Zdenek,
Henderson Michael A.,
Rousseau Roger,
Deskins N. Aaron,
Lyubinetsky Igor
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402599
Subject(s) - redox , chemistry , surface (topology) , environmental chemistry , chemical physics , nanotechnology , mineralogy , materials science , chemical engineering , inorganic chemistry , geometry , engineering , mathematics
By using a combination of scanning tunneling microscopy (STM), density functional theory (DFT), and secondary‐ion mass spectroscopy (SIMS), we explored the interplay and relative impact of surface versus subsurface defects on the surface chemistry of rutile TiO 2 . STM results show that surface O vacancies (V O ) are virtually absent in the vicinity of positively charged subsurface point defects. This observation is consistent with DFT calculations of the impact of subsurface defect proximity on V O formation energy. To monitor the influence of such lateral anticorrelation on surface redox chemistry, a test reaction of the dissociative adsorption of O 2 was employed and was observed to be suppressed around them. DFT results attribute this to a perceived absence of intrinsic (Ti), and likely extrinsic interstitials in the nearest subsurface layer beneath inhibited areas. We also postulate that the entire nearest subsurface region could be devoid of any charged point defects, whereas prevalent surface defects (V O ) are largely responsible for mediation of the redox chemistry at the reduced TiO 2 (110).