Method and apparatus for determining relative surface areas of a coated material on a substrate

Claim 1

A method of determining the proportion of the surface area of a solid support that is covered by a catalytic material which comprises passing a known volume of an adsorbate gas under controlled steady-state conditions of pressure, temperature, and flow rate, over a catalyst material deposited on a solid support maintained at a selected low temperature near the liquefaction temperature of said adsorbate gas and determined first the desorption kinetics of the adsorbate gas adsorbed on said catalyst and said support by heating said catalyst material and said support from near said liquefaction temperature to ambient temperature and continuously measuring the volume of adsorbate gas desorbed from said catalyst material and from said support so as to generate data representing the volume of adsorbate gas adsorbed as a function of temperature; in a similar fashion determining secondly the desorption kinetics of said adsorbate gas adsorbed on said catalyst in the absence of said solid support at the same range of temperatures; in a similar fashion determining thirdly the desorption kinetics of said adsorbate gas adsorbed on said solid support in the absence of said catalyst at the same range of temperatures; comparing the above-determined said first, second and third desorption kinetics of adsorbate gas over identical temperature ranges and calculating therefrom the proportion of surface area of said catalyst material deposited on a solid support that is covered by said catalyst material.

Claim 2

A method of determining the proportion of the surface area of a solid support that is covered by a catalytic material which comprises passing a known volume of an adsorbate gas under controlled steady-state conditions of pressure, temperature, and flow rate, over a catalyst material deposited on a solid support maintained at a selected low temperature near the liquefaction temperature of said adsorbate gas and determined first the desorption kinetics of the adsorbate gas adsorbed on said catalyst and said support by heating said catalyst material and said support from near said liquefaction temperature to ambient temperature and continuously measuring the volume of adsorbate gas desorbed from said catalyst material and from said support so as to generate data representing the volume of adsorbate gas adsorbed as a function of temperature; in a similar fashion determining secondly the desorption kinetics of said adsorbate gas adsorbed on said catalyst in the absence of said solid support at the same range of temperatures; in a similar fashion determining thirdly the desorption kinetics of said adsorbate gas adsorbed on said solid support in the absence of said catalyst at the same range of temperatures; comparing the above-determined said first, second and third desorption kinetics of adsorbate gas over identical temperature ranges and calculating therefrom the proportion of surface area of said catalyst material deposited on a solid support that is covered by said catalyst material.

Claim 5

An apparatus for determination of the surface area of a solid support that is covered by a catalyst material which comprises a thermal conductivity cell having a first and a second subcell for separately measuring and recording thermal conductivities of gases passing therethrough; a mixing tank connected to the inlet of said first subcell, means for introducing into said mixing tank a controlled proportion of a carrier gas and an adsorbate gas at a selected flow rate, a sample cell for receiving gas from said first subcell and immediately into contact with the surface of a sample of said solid support covered by the catalyst material in said sample cell and thereafter immediately conducting the gas to said second subcell; means to measure the temperature of said sample; means to maintain said sample at a selected temperature, and means to measure the flow rate of said gas passing through said second subcell.

Claim 6

An apparatus for determination of the surface area of a solid support that is covered by a catalyst material which comprises a thermal conductivity cell having a first and a second subcell for separately measuring and recording thermal conductivities of gases passing therethrough; a mixing tank connected to the inlet of said first subcell, means for introducing into said mixing tank a controlled proportion of a carrier gas and an adsorbate gas at a selected flow rate, a sample cell for receiving gas from said first subcell and immediately into contact with the surface of a sample of said solid support covered by the catalyst material in said sample cell and thereafter immediately conducting the gas to said second subcell; means to measure the temperature of said sample; means to maintain said sample at a selected temperature, and means to measure the flow rate of said gas passing through said second subcell.