Carbon Nanotubes–Nanoporous Anodic Alumina Composite Membranes: Influence of Template on Structural, Chemical, and Transport Properties

Abstract

This work presents the synthesis of carbon nanotubes–nanoporous anodic alumina composite membranes (CNTs–NAAMs) with controllable geometric features by a template-assisted catalyst-free chemical vapor deposition (CVD) approach using a mixture of toluene and ethanol as a carbon precursor. NAAMs templates were prepared by anodization of aluminum substrates in different electrolytes containing sulfuric, oxalic, and phosphoric acids with the aim of establishing the template effect on the CNTs growth. The deposition time during the CVD process was systematically modified to determine the formation mechanism of CNTs inside the pores of NAAMs without using metal catalysts. The structural features, chemical composition, and graphitic structures of the resulting CNTs–NAAMs composites were characterized by different techniques to provide a comprehensive understanding of the effect of the template on the formation of these carbon-based nanostructures. CNTs–NAAMs with inner pore diameters ranging from 15 to 180 nm we...