Pore size assessment based on wall collision broadening of spectral lines of confined gas: experiments on strongly scattering nanoporous ceramics with fine-tuned pore sizes
- 344 Downloads
Wall collision broadening of absorption lines of gases confined in porous media is a recently opened domain of high-resolution spectroscopy. Here, we present an experimental investigation of its application for pore size assessment. We report on the manufacturing of nanoporous zirconia ceramics with well-defined pore sizes fine-tuned from 50 to 150 nm. The resulting pore structure is characterized using mercury intrusion porosimetry, and the optical properties of these strongly scattering materials are measured using femtosecond photon time-of-flight spectroscopy (transport mean free paths found to be tuned from 2.3 to 1.2 μm as the pore size increase). Wall collision line broadening is studied by performing near-infrared (760 nm) high-resolution diode laser spectroscopy of confined oxygen molecules. A simple method for quantitative estimation of the pore size is outlined and shown to produce results in agreement with mercury intrusion porosimetry. At the same time, the need for improved understanding of wall collision broadening is emphasized.
KeywordsPorous Medium Mercury Intrusion Porosimetry Tunable Diode Laser Absorption Spectroscopy Wall Collision Barium Borate
This work was supported by the Swedish Research Council through a direct grant, a Linnaeus grant to the Lund Laser Centre, and a postdoctoral fellowship granted to T.S. This work also benefited from the Network of Excellence on Nanophotonics for Energy Efficiency.
- 2.P. Wong, Methods in the Physics of Porous Media (Academic Press, San Diego, 1999) Google Scholar
- 6.F. Rouquérol, J. Rouquérol, K.S.W. Sing, Adsorption by Powders and Porous Solids: Principles, Methodology and Applications (Academic Press, San Diego, 1999) Google Scholar