Based on the experimentally determined framework structure of porous MnO2 octahedral molecular sieve (OMS)-5, we used density functional theory-based calculations to evaluate the effect of Na+ cation on pore dimensionality and structural stability, and the interaction between CO2 and OMS-5. We quantified the formation energy of one CO2/unit tunnel and two CO2/unit tunnel, and projected the electronic density of states on the OMS-5 framework, CO2 molecules, and Na+ cations to reveal their individual contributions and bonding nature. Partial charge densities were also calculated to investigate CO2 adsorption behavior in the OMS-5. Our studies predict the initial stage and driving force for the adsorption of CO2 in the OMS-5, guiding the OMS material design for carbon capture and storage applications.

Porous CoO/Mn2O3 Fischer-Tropsch (F-T) catalysts have been studied in CO hydrogenation. These CoO/Mn2O3 catalysts have been synthesized by incipient wetness impregnation method. These mesoporous catalysts have pore diameters of 2-25 nm and a surface area of 9.0 m2/g. The gas and liquid products have been analyzed by an online gas chromatograph. The solid products were characterized by gas chromatograph-mass spectroscopy. These microsize cobalt catalysts exhibit good activity with 72.1% CO conversion and they are very stable in a 48 h stream test at 280ºC. The selectivity to paraffins is above 95%. Few wax products were synthesized with a yield of less than 2%. The size effects of the cobalt catalysts have been studied by scanning electron microscopy.

Interface coatings on fibers are important in ceramic matrix composites. In addition to providing toughness, the interface coating must also protect the reinforcing ceramic fibers from corrosive degradation. A double interface coating has been applied onto silicon carbide fibers. The double interface coating is comprised of a combination of nitride and oxide coatings. Among the nitrides, boron nitride and titanium nitride were utilized. These nitrides were deposited by CVD. The metal oxides of choice were aluminum oxide and zirconium oxide which were applied onto the nitride coatings by MOCVD. The phases on the coated fibers were determined by XRD. The surface coating microstructures were observed by SEM. The effect of the coatings on the tensile strengths was determined by Instron tensile strength measurements.

High temperature materials such as nickel superalloys require the development of corrosion resistant coatings. These coatings must be thermally stable and chemically inert in order to protect the substrate material. Aluminum oxide is one such candidate. Aluminum acetylacetonate was used as the precursor for metal-organic chemical vapor deposition at atmospheric pressure. Uniform, amorphous, and multi-colored protective coatings were deposited onto nickel substrates at 400 to 500°C and dark gray, and powdery coatings were obtained at higher temperatures of 550 to 600°C. The coating was free from cracks when higher carrier gas flow rate were used.

Three cross-linking reagents (PVA, glycerol and glucose) have successfully been used to synthesize non-doped and metal-doped nanosized cryptomelane materials via a solid-state preparation method. The 2×2 tunnel structure of cryptomelane was formed at 500 °C. FT-IR data show that no cross-linking reagent residues were found in the products after the reactions were complete at 800 °C. The metal dopants used were Fe, Ag, Co, Cu, Ni, and Zn. XRD data show that Fe and Co cations can be doped into the materials without the formation of additional phases. The tunnel structures of the nanosized materials exhibit long-range along the b axis, as indicated by transmission electron microscopy data. High-resolution scanning electron microscopy studies show that morphologies of the products are nanorods or nanofibers, depending on the cross-linking reagents used in the preparation. Thermogravimetric analyses indicate that these nanomaterials are thermally stable to 700 °C.

Sponge type deposits composed of nanometer sized Si whiskers were formed on Davisil (porous SiO2) gel substrates by chemical vapor deposition (CVD) using methyltrichlorosilane (MTS) as a precursor and H2 as carrier gas. The diameters of the fine whiskers are estimated to be 100 nm or smaller from SEM observations. XRD analyses revealed that the coatings formed at 800 and 900°C contained microcrystalline Si and the Auger analysis indicated the existence of free carbon. The surface area of the coated Davisil was approximately 189 ± 5 m2/g, as obtained from BET measurements. The coatings were also applied on several other substrates, such as AIN and low surface area (< 224 m2/g) silica gel, with the same coating conditions. On these substrates, highly porous Si has also been observed on AIN substrates, and nonporous, half sphere shaped coatings were observed on low surface area silica gel substrates.

Coating of SiC (BP-SIGMA) fibers with alumina by a sol-gel process did not cause degradation even after heating to 1000°C in air for 24 h. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Auger electron spectroscopy (AES) and scanning electron microscopy (SEM ) methods were used to study the coating fiber interface.

Thin film coatings of NaY, NaA and ZSM-5 zeolites have been grown on copper and platinum substrates. Such materials have ion-exchange properties, molecular sieve pore size distribution, zeolitic surface areas and are crystalline. Size and charge selective electrodes, oxygen reduction fuel cells, and thin layer chromatography devices have been produced with these materials.

A process involving dip coating of ceramic fibers in H3BO3 solution followed by reaction with NH3 has resulted in the formation of a BN coating on Nicalon and a carbon coated Nicalon fiber. BN coated C-Nicalon fiber maintained its strength during the coating process, while the BN coated Nicalon did not.

SICABO fiber, which is one of the silicon carbide coated fibers, has been found to be more stable than BORSIC fiber in titanium matrix composites because SICABO fiber has excess carbon in the SiC layer which was determined by an AES depth profile study. Tensile strength data also show that the SICABO fiber has a higher tensile strength after heating in titanium during hot pressing and chemical vapor deposition processing. Ti5Si3 and TiSi phases were identified from XRD studies on titanium coated BORSIC, but there was no TiSi phase identified in the titanium coated SICABO fiber. AES depth profile results have shown that the BORSIC-Ti has a broad interdiffusion zone.