A RELIABLE MODEL TO CHARACTERIZE NANOPOROUS CMK-3 CARBON MATERIALS

V. YELPO; CORNETTE V.; D. BARRERA; K. SAPAG; R. LÓPEZ

Cartagena de Indias

Encuentro; 2° Iberoamericano de Adsorción; 2015

Universidad de los Andes

The design and study of new materials with specific properties is interesting in several scientific and technological fields. In the last years, nanostructured carbons (NC) have rapidly attracted the attention of some researchers due to their physicochemical properties useful for many applications among them in adsorption and catalysis. NCs are a class of important porous materials that allow precise control over the pore size and arrangement over a wide range, which is vital for applications requiring size and shape selectivity, hierarchical material organization, and pore accessibility. Recently, Ryoo and co-workers synthesized an ordered mesoporous carbon named CMK-3, which consists of two-dimensional (2D) hexagonal arrays of carbon nanorods, and where the pore size distribution (PSD) is usually obtained assuming that consists of a collection of unconnected ?ideal? cylindrical (or slit-shaped) pore or a combination of both geometries (mixed model). However, the emergence of these novel materials with pre-designed pore morphology requires the development of new methods, which take into account the morphological specifics of these structures. Based on CMK-3 carbons synthesized by Ryoo et al. and by Barrera et al., the nitrogen experimental isotherms were simulated using Grand Canonical Monte Carlo (GCMC) method based on two kernels using slit and cylindrical pore models. From these models were obtained the PSD´s which were compared with those obtained by Quenched Solid Density Functional Theory (QSDFT) model. Finally a more detailed molecular model, considering the morphology of CMK3 pore, is studied by GCMC showing a good agreement with experimental adsorption isotherms and some differences with the corresponding pore size distribution obtained by Density Functional Theories Methods. These correlations validate the presented GCMC method as an alternative to study in detail the porosity of these materials.