Mesoporous Carbon/Zirconia Composites: A Potential Route to Chemically Functionalized Electrically-Conductive Mesoporous Materials

Mesoporous nanocomposite materials in which nanoscale zirconia (ZrO₂) particles are embedded in the carbon skeleton of a templated mesoporous carbon matrix were prepared, and the embedded zirconia sites were used to accomplish chemical functionalization of the interior surfaces of mesopores. These nanocomposite materials offer a unique combination of high porosity (e.g., ∼84% void space), electrical conductivity, and surface tailorability. The ZrO₂/carbon nanocomposites were characterized by thermogravimetric analysis, nitrogen-adsorption porosimetry, helium pychnometry, powder X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Comparison was made with templated mesoporous carbon samples prepared without addition of ZrO₂. Treatment of the nanocomposites with phenylphosphonic acid was undertaken and shown to result in robust binding of the phosphonic acid to the surface of ZrO₂ particles. Incorporation of nanoscale ZrO₂ surfaces in the mesoporous composite skeleton offers unique promise as a means for anchoring organophosphonates inside of pores through formation of robust covalent Zr–O–P bonds

Thermal Processing as a Means to Prepare Durable, Submicron Thickness Ionomer Films for Study by Transmission Infrared Spectroscopy

A high temperature solution processing method was adapted to prepare durable, freestanding, submicrometer thickness films for transmission infrared spectroscopy studies of ionomer membrane. The materials retain structural integrity following cleaning and ion-exchange steps in boiling solutions, similar to a commercial fuel cell membrane. Unlike commercial membrane, which typically has thicknesses of >25 μm, the structural properties of the submicrometer thickness materials can be probed in mid-infrared spectral measurements with the use of transmission sampling. Relative to the infrared attenuated total reflection (ATR) technique, transmission measurements can sample ionomer membrane materials more uniformly and suffer less distortion from optical effects. Spectra are reported for thermally processed Nafion and related perfluoroalkyl ionomer materials containing phosphonate and phosphinate moieties substituted for the sulfonate end group on the side chain. Band assignments for complex or unexpected features are aided by density functional theory (DFT) calculations