American Chemical Society
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Water Photooxidation by TiSi2–TiO2 Nanotubes

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journal contribution
posted on 2011-06-30, 00:00 authored by Subarna Banerjee, Susanta K. Mohapatra, Mano Misra
A composite photocatalyst comprised of self-assembled titania (TiO2) nanotubes (NTs) coupled with titanium disilicide (TiSi2) nanoparticles has been synthesized, characterized, and tested for photoelectrochemical hydrogen generation. The TiO2 NT array is prepared by a sonoelectrochemical anodization method using ethylene glycol, ammonium fluoride, and disodium salt of ethylene diaminetetraacetic acid (Na2[H2EDTA]). TiSi2 nanoparticles are produced from commercial bulk particles by a multiple ball milling followed by an ultrasonication process. The coupled catalyst is prepared by impregnating TiSi2 nanoparticles into the TiO2 nanotubes by multiple soaking processes, which leads to a noble structure with TiSi2 nanorods inside the TiO2 nanotubes. The heterostructural composite photoanode exhibited an enhanced photocurrent density of 3.49 mA/cm2 at 0.2 VAg/Ag/Cl compared to TiO2 nanotubes alone (0.9 mA/cm2) and can be considered as a potential possible candidate for the water splitting reaction using visible light. Pure TiSi2 particles coated on ITO are also evaluated for the water splitting reaction, and it is found that TiSi2 possesses good visible light activity (around 55% of the total activity). The combined light absorption (both UV and visible regions) of TiSi2–TiO2 NT material as evident from experimental results and the high charge transport properties of a self-assembled one-dimensional nanotube array make the composite potentially promising.