Aqueous solutions were prepared with 18.0 MX cm Milli-Q UV Plus deionized
water. VA-MWNTs were synthesized on a silicon wafer via a
conventional-pressure, chemical vapor deposition (CVD) method at 900 C in a mixture of H2/Ar (15:85, v/v), using solid iron (III) phthalocyanine (purity > 99%, Sigma) as a carbon- and catalystsource [33].
The VA-MWNTs were transferred to a conducting carbon-
based composite membrane by following the same procedure
as reported previously [34].