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Titania Morphology‐Dependent Gold–Titania Interaction, Structure, and Catalytic Performance of Gold/Titania Catalysts
Author(s) -
Chen Shilong,
Zhang Bingsen,
Su Dangsheng,
Huang Weixin
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201500599
Subject(s) - anatase , catalysis , morphology (biology) , stoichiometry , materials science , chemical engineering , nanoparticle , nanocrystal , nanotechnology , inorganic chemistry , photocatalysis , chemistry , organic chemistry , biology , engineering , genetics
Employing anatase TiO 2 nanocrystals with predominantly {0 0 1} facets, anatase TiO 2 nanocrystals with predominantly {1 0 0} facets, and TiO 2 P25 with predominantly {1 0 1} facets as supports, we have comprehensively studied the morphology effect of TiO 2 on the Au‐TiO 2 interaction, structure, and catalytic performance of Au/TiO 2 catalysts in C 3 H 6 epoxidation with H 2 and O 2 , C 3 H 6 oxidation with O 2 , and H 2 oxidation. A strong morphology‐dependent interplay between the Au‐TiO 2 interaction and the catalyst structure was observed. Only Au nanoparticles were present in the Au/TiO 2 catalysts and the Au δ− species was the largest in Au/TiO 2 {0 0 1} due to the creation of surface O vacancies of TiO 2 {0 0 1} upon Au loading, whereas the fraction of Au δ+ species was largest in Au/TiO 2 {1 0 0} due to the preserved surface stoichiometry of TiO 2 {1 0 0} upon Au loading. In H 2 oxidation, Au/TiO 2 {1 0 0} with the largest fraction of Au δ+ species was the most active but least selective toward H 2 O 2 , whereas Au/TiO 2 {0 0 1} with the largest fraction of Au δ− species was the most selective toward H 2 O 2 . In C 3 H 6 oxidation with O 2 , tiny C 3 H 6 conversions with the formation of partial oxidation products were observed at low temperatures, whereas C 3 H 6 combustion occurred at high temperatures. In C 3 H 6 epoxidation with O 2 and H 2 , the ensemble consisting of closely connected Au δ− and Ti 4+ on anatase TiO 2 {0 0 1} and {1 0 1} facets with weak adsorption ability was the active structure and the Au/TiO 2 {0 0 1} catalyst containing the largest amount of this ensemble was the most active. These results demonstrated morphological engineering of oxides as an effective strategy to optimize the catalytic performance and understand the fundamentals of catalysis involving oxides.