Exotemplating synthesis of nitrogen-doped carbon materials with hierarchically porous structure and their application for lysozyme adsorption

Abstract

Nitrogen-doped carbon materials with hierarchically porous structure were prepared by employing meso-/macroporous titania (MMT) as exotemplate with the use of Vitamin B6 (VB6) as both the carbon precursor and the nitrogen source for elemental doping. The synthesized materials were characterized by N 2 sorption, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The obtained N-doped carbon materials have a multi-scaled porous hierarchy with pore sizes ranging from micropores, mesopores to macropores, and their morphology can be easily tuned through a simple adjustment of the weight ratio of VB6 to MMT. The different chemical state (pyridine-like N, quaternary N and oxidized N) and the content of nitrogen were analyzed by XPS. The prepared materials were used as the adsorbents for lysozyme. The effect of nitrogen doping on the lysozyme adsorption capability was investigated by comparison of the lysozyme adsorption behavior on the nitrogen-doped and nitrogen-free carbon materials with a similar pore structure. It was found that the nitrogen-containing carbon had higher adsorption capacity of lysozyme than that of the nitrogen-free carbons.