Fabrication of Hierarchical N-doped Carbon Nanotubes for CO2 Adsorption

Abstract

Hierarchical N-doped carbon nanotubes (NCTs) with controllable aspect ratios were developed for CO2 adsorption. In this work, NCTs were synthesized by coating different amounts of 3-aminophenol/formaldehyde resin (APF) on the outer layer of silica nanotubes, carbonizing in N2 at 700∘C and removing the silica and Ni template by hydrofluoric acid etching. The obtained NCTs were activated by K2CO3. After activation, micropores on the activated N-doped carbon nanotubes (ANCTs) were enriched, the micro-surface area and pore volume of ANCT-1.0 reached 1195[Formula: see text]m2[Formula: see text]g[Formula: see text] and 0.45[Formula: see text]cm3[Formula: see text]g[Formula: see text], respectively, and the corresponding adsorption capacity increased by 50% (4.50[Formula: see text]mmol[Formula: see text]g[Formula: see text] at 0∘C and 1 bar). Moreover, ANCT-1.0 maintained a high stability throughout consecutive adsorption–desorption cycles. The advantages of hierarchical N-doped carbon nanotubes, including their meso–microporous structures, high geometric aspect ratio and good stability, make them valuable and promising materials to capture carbon dioxide.