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This paper deals with preparing a functional composite carbon fiber with a large surface area for spilled oil cleaning. The composite fiber consisted of photosensitive oxide particles and polymer-derived carbon. It was made by co-spinning the polymer and metallic compounds. After heat treatment at high temperatures, an activated carbon fiber containing oxide particles was obtained. The particles were found distributed in the fiber and at the surface of the fiber. The composite fiber was found sensitive to sunlight. Fiber mats made of the composite fiber possessed a high surface area for oil absorption and removal. Cobalt(II) titanate particles were obtained from the reaction of titanium dioxide and cobalt oxide. The reaction happened in situ through the hydrolysis of metallic compounds in the spun fiber. The titanium dioxide and cobalt(II) titanate particle-containing fibers demonstrated the photoactivity in the visible light spectrum. It was concluded that particle-containing composite carbon fiber mats can be prepared successfully by co-electrospinning. Due to the oleophilic property and the high active surface area, the composites are suitable for spilled oil cleaning through fast absorption.

This article provides an overview on manufacturing composite carbon nanofiber-based aerogels through freeze casting technology. As known, freeze casting is a relatively new manufacturing technique for generating highly porous structures. During the process, deep cooling is used first to rapidly solidify a well-dispersed slurry. Then, vacuum drying is conducted to sublimate the solvent. This allows the creation of highly porous materials. Although the freeze casting technique was initially developed for porous ceramics processing, it has found various applications, especially for making aerogels. Aerogels are highly porous materials with extremely high volume of free spaces, which contributes to the characteristics of high porosity, ultralight, large specific surface area, huge interface area, and in addition, super low thermal conductivity. Recently, carbon nanofiber aerogels have been studied to achieve exceptional properties of high stiffness, flame-retardant and thermal-insulating. The freeze casting technology has been reported for preparing carbon nanofiber composite aerogels for energy storage, energy conversion, water purification, catalysis, fire prevention etc. This review deals with freeze casting carbon nanofiber composite materials consisting of functional nanoparticles with exceptional properties. The content of this review article is organized as follows. The first part will introduce the general freeze casting manufacturing technology of aerogels with the emphasis on how to use the technology to make nanoparticle-containing composite carbon nanofiber aerogels. Then, modeling and characterization of the freeze cast particle-containing carbon nanofibers will be presented with an emphasis on modeling the thermal conductivity and electrical conductivity of the carbon nanofiber network aerogels. After that, the applications of the carbon nanofiber aerogels will be described. Examples of energy converters, supercapacitors, secondary battery electrodes, dye absorbents, sensors, and catalysts made from composite carbon nanofiber aerogels will be shown. Finally, the perspectives to future work will be presented.

In this work, cobalt acetate was incorporated into polyacrylonitrile (PAN) polymer through electrospinning as the cobalt oxide source. After oxidization and pyrolysis, a PAN-derived composite carbon fiber containing cobalt oxide was obtained. Measuring the electrical and photonic properties of the composite fiber under visible light irradiation was performed to evaluate the photoelectric behavior of the composite fiber. The p-type semiconducting behavior of the composite fiber was confirmed by measuring the open circuit voltage of a photochemical fuel cell consisting of the photosensitive electrode made from the composite fiber. The application of the composite fiber for glucose sensing was demonstrated.