Free-standing carbon nanotube-titania photoactive sheets.

Journal of colloid and interface science (2015-03-01)
Youngmi Koo, Rachit Malik, Noe Alvarez, Vesselin N Shanov, Mark Schulz, Jag Sankar, Yeoheung Yun
ABSTRACT

We report on the development of a new photoactive material via titania (TiO2) nanoparticle deposition on free-standing aligned carbon nanotube (CNT) sheets. Controlling homogeneous dispersion of negatively charged TiO2 nanoparticles, achieved by adjusting pH higher than the point of zero charge (PZC), influenced electrochemical deposition of TiO2 on CNT sheets substrate. Varying deposition time with constant voltage, 5 V allowed different thickness of TiO2 to be deposited layer on the CNT sheets. The thickness and morphology of CNT-TiO2 sheets was verified by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Electrochemical experiments show that diffusion coefficient of Fe(CN)6(3-) was 5.56×10(-6) cm(2) s(-1) at pristine CNT sheets and 2.19×10(-6) cm(2) s(-1) at the CNT-TiO2 sheets. Photocatalytic activity for CNT-TiO2 sheets exhibits high photocurrent density (when deposition time=30 min, 4.3 μA cm(-2) in N2, 13.4 μA cm(-2) in CO2). This paper proved a possibility to use CNT-TiO2 sheets based on highly-aligned CNT sheets substrate as new photoactive material.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Ethyl alcohol, Pure, 190 proof, ACS spectrophotometric grade, 95.0%
Sigma-Aldrich
Hydrogen peroxide solution, 30 % (w/w) in H2O, contains stabilizer
Sigma-Aldrich
Titanium(IV) isopropoxide, 97%
Sigma-Aldrich
Titanium(IV) isopropoxide, 99.999% trace metals basis
Sigma-Aldrich
Hydrogen peroxide solution, 34.5-36.5%
Sigma-Aldrich
Titanium(IV) isopropoxide, ≥97.0%
Sigma-Aldrich
Titanium(IV) isopropoxide, packaged for use in deposition systems