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ZnFe 2 O 4 Leaves Grown on TiO 2 Trees Enhance Photoelectrochemical Water Splitting
Author(s) -
Zheng XueLi,
Dinh CaoThang,
de Arquer F. Pelayo García,
Zhang Bo,
Liu Min,
Voznyy Oleksandr,
Li YiYing,
Knight Gordon,
Hoogland Sjoerd,
Lu ZhengHong,
Du XiWen,
Sargent Edward H.
Publication year - 2016
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201600534
Subject(s) - materials science , water splitting , photocatalysis , atomic layer deposition , band gap , visible spectrum , nanotechnology , chemical engineering , nanoparticle , electrochemistry , absorption (acoustics) , optoelectronics , layer (electronics) , catalysis , chemistry , electrode , composite material , engineering , biochemistry
TiO 2 has excellent electrochemical properties but limited solar photocatalytic performance in light of its large bandgap. One important class of visible‐wavelength sensitizers of TiO 2 is based on ZnFe 2 O 4 , which has shown fully a doubling in performance relative to pure TiO 2 . Prior efforts on this important front have relied on presynthesized nanoparticles of ZnFe 2 O 4 adsorbed on a TiO 2 support; however, these have not yet achieved the full potential of this system since they do not provide a consistently maximized area of the charge‐separating heterointerface per volume of sensitizing absorber. A novel atomic layer deposition (ALD)‐enhanced synthesis of sensitizing ZnFe 2 O 4 leaves grown on the trunks of TiO 2 trees is reported. These new materials exhibit fully a threefold enhancement in photoelectrochemical performance in water splitting compared to pristine TiO 2 under visible illumination. The new materials synthesis strategy relies first on the selective growth of FeOOH nanosheets, 2D structures that shoot off from the sides of the TiO 2 trees; these templates are then converted to ZnFe 2 O 4 with the aid of a novel ALD step, a strategy that preserves morphology while adding the Zn cation to achieve enhanced optical absorption and optimize the heterointerface band alignment.