(620d) Characterization of Novel Ordered Mesoporous Carbons
Characterization of Novel Ordered Mesoporous Carbons
Richard Cimino1, Gennady Gor3, Katie A. Cychosz2, Matthias Thommes2 , and Alexander V. Neimark1
(1) Rutgers University, Department of Chemical and Biochemical Engineering,
98 Brett Road, Piscataway, NJ 08854, USA
(2) Quantachrome Instruments, 1900 Corporate Dr., Boynton Beach, FL 33426, USA
(3) Princeton University, Department of Civil and Environmental Engineering, Princeton, NJ USA
During last decade, the density functional theory (DFT) methods of pore size analysis were found to be superior to the traditional thermodynamic methods, like BJH method. DFT methods enable material characterization based on certain assumptions about the underlying geometry of the pore network. After the isotherm calculations are performed for individual pores of given shape within a large range of pore sizes, these theoretical isotherms are compiled into a ‘kernel’, from which the pore size distribution of a material can be determined from the experimental data. Until recently, most DFT methods relied on a single pore shape for kernel computation – either slit, cylindrical, or spherical. However, many materials possess hierarchical structures with micro- and mesopores, which form pore networks of various morphology. For example, the pores in newly discovered three-dimensional ordered mesoporous (3DOm) carbon materials form a regular cubic network of cage-like pores, the size of which can be tailored from 10 to 40 nm. In order to better characterize these and other templated carbons, hybrid kernels were developed with double and triple pore geometries (slit-cylindrical, spherical-cylindrical, slit-cylindrical-spherical). The hybrid methods can approximate the highly complex nature of possible pore structures. To improve our understanding of these materials, kernels were created for both nitrogen and argon adsorption and equilibrium desorption measurements. The validity of these calculations has been checked against traditional methods and previous density functional approaches, and show good agreement. Current research is expected to further optimize the ratio of pore geometries in these hybrid kernels and to improve our understanding of the complex nature of the pore structure of these materials.