Yousheng Tao

Recent progress in the synthesis and applications of nanoporous carbon films

The synthesis and applications of thin nanoporous carbon films or membranes (NPCFs) are outlined with a focus on recent literature examples. NPCFs have large specific surface area, high electrical and thermal conductivity and both chemical and mechanical stability properties that facilitate increasing conventional uses in purification and separation, adsorption, and catalysis. They have potential applications in nanodevices, supercapacitors, lithium ion batteries, and chemical and bio-sensors. We summarize the various NPCF fabrication techniques, including solid- or soft-templating, direct pyrolysis on porous organic polymer precursors, chemical or physical vapor deposition and electrochemical deposition, and highlight the future design trends in the fabrication of NPCFs with ordered nanopore structures.

Hydrophilicity-controlled carbon aerogels with high mesoporosity.

Highly mesoporous carbon aerogels with hydrophilicity-controlled pore walls were synthesized using a unique approach that combines CO(2) supercritical drying and colloidal silica nanocasting. The samples were characterized using nitrogen adsorption at 77 K, water adsorption at 303 K, field-emission scanning electron microscopy (FE-SEM), thermogravimetric analysis, X-ray photoelectron spectroscopy, and Raman spectroscopy. The nitrogen adsorption revealed the presence of micropores and mesopores with narrow pore size distributions. The water adsorption suggested that the hydrophilicity of carbon aerogels can be controlled by the residual silica in their pore walls. The FE-SEM observation confirmed the presence of hierarchical mesostructures and the high mesoporosity. The high surface area, large nanopore volume, and hydrophilicity-controlled pore walls make these aerogels well-suited for many applications.

A Review of Synthesis and Nanopore Structures of Organic Polymer Aerogels and Carbon Aerogels

Organic polymer aerogels and carbon aerogels are important nanoporous materials, of which the nanopore structures can be modified by the chemical reactions. These materials have received considerable attention in fundamentals on materials science and commercial applications. This paper discusses with the current patents involving in synthesis and modifications of nanostructures and surfaces of organic polymer aerogels and carbon aerogels. It emphasizes the recent developments in fabrication pathways of lower cost and their applications for template synthesis and nanostructural assembling.

High capacitance carbon-based xerogel film produced without critical drying

We report the production of carbon-based xerogel film without the need for supercritical drying. Xerogel samples were characterized with field emission scanning electron microscopy, nitrogen adsorption/desorption at 77 K, Raman spectroscopy, thermogravimetric analysis, and electrical conductivity and cyclic voltammetry measurements. Experimental results reveal that the film is largely crack free and homogeneous in thickness, and, importantly, has high surface area, large nanopore volume, and an excellent performance for electrical charge storage—both per unit mass and unit volume. These results indicate that the film has potential applications for electrical energy storage devices.

Pore Structures of ZSM-5 Synthesized in the Mesopore Spaces of a Carbon Aerogel

A mesoporous ZSM-5 monolith several millimetres in size has been synthesized employing the template method and using a carbon aerogel with uniform mesopores. Measurement of the pore-size distribution using nitrogen adsorption showed a bimodal pore system of mesopores and micropores whose average pore widths were 8 nm and 0.51 nm, and whose volumes were 0.09 cm3/g and 0.34 cm3/g, respectively.

Fundamental Understanding of Nanoporous Carbons for Energy Application Potentials

The importance of nanopore structures of carbons is shown in terms of interaction potential for various molecules including supercritical gases such as and . The key factors for adsorption of supercritical and are shown for single wall carbon nanohorn, single wall carbon nanotube, and double wall carbon nanotube. The cluster formation of molecules is a key process for water adsorption on hydrophobic carbon nanopores. The X-ray absorption spectroscopic examination elucidates an explicit dehydration structure of ions confined in carbon nanopores.

Characterization of alkaline post-treated ZSM-5 zeolites by low temperature nitrogen adsorption

ZSM-5 zeolites having SiO 2 /Al 2 O 3 molar ratios of 23.8 and 200 were treated in 0.05 M NaOH solutions at 325 K. The pore structure changes were investigated by low temperature nitrogen and argon adsorption. The mesopores with broad mesopore size distributions were developed after alkaline treatment of ZSM-5 with a low SiO 2 /Al 2 O 3 molar ratio 23.8. Alkaline treatment of ZSM-5 with a high SiO 2 /Al 2 O 3 molar ratio 200 gave no mesopores from both nitrogen and argon adsorption measurements. Formation of defect-cluster associated pores in ZSM-5 zeolite upon alkaline post-treatment is discussed.