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Light‐Induced Motion of Microengines Based on Microarrays of TiO 2 Nanotubes
Author(s) -
Enachi Mihail,
Guix Maria,
Postolache Vitalie,
Ciobanu Vladimir,
Fomin Vladimir M.,
Schmidt Oliver G.,
Tiginyanu Ion
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.201601680
Subject(s) - microscale chemistry , materials science , photocatalysis , nanotechnology , titanium dioxide , nanotube , nanoscopic scale , conical surface , nanomaterials , chemical engineering , carbon nanotube , catalysis , composite material , chemistry , biochemistry , mathematics education , mathematics , engineering
An electrochemical approach for manufacturing light‐driven nanostructured titanium dioxide (TiO 2 ) microengines with controlled spatial architecture for improved performance is reported. The microengines based on microscale arrays of TiO 2 nanotubes with variable (50–120 nm) inner diameter show a quasi‐ordered arrangement of nanotubes, being the smallest tubular entities for catalytic microengines reported to date. The nanotubes exhibit well defined crystalline phases depending upon the postfabrication annealing conditions that determine the microengines' efficiency. When exposed to UV‐light, the microarrays of TiO 2 nanotubes exhibiting conical internal shapes show directed motion in confined space, both in the presence and absence of hydrogen peroxide. In the former case, two different motion patterns related to diffusiophoresis and localized nanobubble generation inside of the tubes due to the photocatalytic decomposition of H 2 O 2 are disclosed. Controlled pick‐up, transport, and release of individual and agglomerated particles are demonstrated using the UV light irradiation of microengines. The obtained results show that light‐driven microengines based on microarrays of TiO 2 nanotubes represent a promising platform for controlled micro/nanoscale sample transportation in fluids as well as for environmental applications, in particular, for the enhanced photocatalytic degradation of organic pollutants due to the improved intermixing taking place during the motion of TiO 2 microengines.