Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7834443 | Applied Surface Science | 2018 | 9 Pages |
Abstract
Anatase TiO2 micro-crystals with 51% surface exposing highly active {0â¯0â¯1} facets are prepared by hydrothermal synthesis using TiF4 as Ti resource and HF as morphology control agent. In addition, anatase TiO2 single crystals exposing large {0â¯0â¯1} crystal facets are facilely synthesized with “green” NaF plus HCl replacing HF for the morphology control. A series of comparative experiments are carried out for separately studying the effects of Fâ and H+ concentrations on the growth of TiO2 crystals, which have not been understood very much in depth so far. The results indicate that both Fâ and H+ synergistically affect the synthesis of truncated anatase octahedrons, where Fâ is preferentially adsorbed on the {0â¯0â¯1} facets resulting in lateral growth of these facets and H+ adjusts the growth rate of anatase TiO2 along different orientations by tuning the hydrolysis rate. Based on this information, anatase TiO2 single crystals with small size (1.3â¯Î¼m) and large exposure of {0â¯0â¯1} facets (45%) are successfully prepared under optimal conditions ([H+]/[Fâ]â¯=â¯20:1). Photocatalytic activities of the as-prepared products toward methylene blue photo-degradation are further tested. It is revealed that both crystal size and percentage of {0â¯0â¯1} facets are decisive for the photocatalytic performance, and the crystals with a small size (1.3â¯Î¼m) and large exposure of {0â¯0â¯1} facets (45%) are catalytically most active. This work has clarified the main factors that control the growth process and morphology of anatase TiO2 single crystals for achieving superior photocatalytic properties.
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Authors
Huifen Tong, Yingying Zhou, Gang Chang, Pai Li, Ruizhi Zhu, Yunbin He,