HorvathKawazoe

HorvathKawazoe refers to the Horvath–Kawazoe method, a pore-size analysis technique used in material science to estimate micropore size distributions from gas adsorption isotherms, most commonly nitrogen adsorption at 77 K. Developed by Horvath and Kawazoe in the mid-1990s, the method combines a geometric pore model with an energy-based criterion for adsorption to infer the distribution of micropore widths from adsorption data.

The approach treats micropores as narrow cylindrical (and sometimes slit-like) passages and computes the potential energy landscape experienced by an adsorbate molecule near the pore walls. For a given pore width, it determines the largest radius that can accommodate adsorption at a particular relative pressure, based on the energy criterion. By translating relative pressure into pore width, the method yields a differential pore volume as a function of pore size, which forms the Horvath–Kawazoe pore-size distribution.

Applications of the method include characterization of microporosity in activated carbons, carbon blacks, and other porous carbons, as well as in some inorganic materials such as silica and certain zeolites. It is particularly used to analyze pores below about 2 nanometers in width.

Limitations and considerations: the method relies on simplifying assumptions about pore geometry and the interaction potential, which may not capture complex pore networks or non-cylindrical geometries. It is most reliable for rigid, predominantly microporous materials with high-quality adsorption data. For broader pore systems, alternative methods such as t-plot, BJH, or density functional theory (DFT)–based approaches may be more appropriate.

References: The original concept was introduced in a 1995 publication by Horvath and Kawazoe; subsequent literature discusses its applications and limitations.