Method for combined characterization of pore structure

A method for combined characterization of a pore structure, comprising:

• S1, collecting actual measurement data of pore diameter ranges characterized by a carbon dioxide (CO2) adsorption, a nitrogen (N2) adsorption, and a mercury intrusion porosimetry;
• wherein the actual measurement data comprises a pore diameter and a pore volume;
• for the CO2 adsorption, taking the actual measurement data for the pore diameter less than 3 nanometers (nm), for the N2 adsorption, taking the actual measurement data for the pore diameter in a range of 1.6-200 nm, and for the mercury intrusion porosimetry, taking the actual measurement data for the pore diameter in a range of 20-100,000 nm;
• S2, plotting pore characterization curves with the pore diameter as a horizontal coordinate and the pore volume as a vertical coordinate based on the actual measurement data to obtain a CO2 characterization curve, a N2 characterization curve, and a mercury intrusion porosimetry characterization curve, respectively;
• S3, performing data processing on an overlapping range of the pore diameter between the CO2 characterization curve and the N2 characterization curve, wherein the pore diameter in the overlapping range is in a range of 1.6 nm-3 nm;
• wherein the step S3 specifically comprises:
• S31, taking an average value of pore volume data in the overlapping range of the pore diameter between the CO2 characterization curve and the N2 characterization curve, specifically, calculating an average value of a CO2 pore volume and a N2 pore volume corresponding to a same pore diameter, then forming a discrete point list of data points [xi, yi] based on the average value of the pore volume and the pore diameter in the overlapping range, wherein xi represents the pore diameter, yi represents the average value of the pore volume, and i represents a number of the data points in the overlapping range, with i taking a value greater than or equal to 8;
• S32, fitting a curve of yi′=ƒ(x) passing through all the data points in the discrete point list based on the discrete point list of the data points [xi, yi], thereby obtaining the function of yi′=ƒ(x);
• wherein the step S32 specifically comprises:
• letting an equation passing through a first point (xi, yi) be defined as follows:
• y=y1 (equation 1),
• letting an equation passing through a second point (x2, y2) be defined as follows:
• y=y1+a0(x−x1) (equation 2),
• substituting the second point (x2, y2) into the equation 2 to obtain a0;
• letting an equation passing through a third point (x3, y3) be defined as follows:
• y=y1+a0(x−x1)+a1(x−x1)(x−x2) (equation 3),
• substituting the third point (x3, y3) into the equation 3 to obtain a1;
• letting an equation passing through a third point (x4, y4) be defined as follows:
• y=y1+a0(x−x1)+a1(x−x1)(x−x2)+a2(x−xi)(x−x2)(x−x3) (equation 4),
• substituting the third point (x4, y4) into the equation 4 to obtain a2;
• sequentially obtaining a3, a4, a5 . . . ai-2 based on the S32 based on the above equation defined means;
• and
• followed by obtaining the function of yi′=ƒ(x) between the overlapping range of the CO2 adsorption and the N2 adsorption based on the obtained a0, a1, a2 . . . ai-2 as follows:
• y=y1+a0(x−x1)+a1(x−x1)(x−x2)+a2(x−x1)(x−x2)(x−x3)+a3(x−x1)(x−x2)(x−x3)(x−x4)+ . . . +ai-2(x−xi)(x−x2)(x−x3)(x−x4) . . . (x−xi-2)(x−xi-1) (equation 5);
• S33, substituting each pore diameter xi into the function yi′=ƒ(x) to calculate the corresponding pore volume yi′ of each pore diameter xi, plotting the curve with the pore diameter xi as the horizontal coordinate and the pore volume yi′ as the vertical coordinate to obtain a characterization curve of the overlapping range of the pore diameter between the CO2 characterization curve and the N2 characterization curve;
• S4, performing data processing on an overlapping range of the pore diameter between the N2 characterization curve and the mercury intrusion porosimetry characterization curve, wherein the overlapping range of the pore diameter between the N2 characterization curve and the mercury intrusion porosimetry characterization curve is in a range of 20 nm-200 nm, processing steps are the same in the steps S31 to S33, thereby to obtain a characterization curve of the overlapping range of the pore diameter between the N2 characterization curve and the mercury intrusion porosimetry characterization curve;
• and
• S5, splicing and combining the characterization curve of the overlapping range of the pore diameter between the CO2 characterization curve and the N2 characterization curve, the characterization curve of the overlapping range of the pore diameter between the N2 characterization curve and the mercury intrusion porosimetry characterization curve, with the CO2 characterization curve, the N2 characterization curve, and the mercury intrusion porosimetry characterization curve, thereby obtaining a combined characterization curve of the pore structure based on the CO2 adsorption, the N2 adsorption, and the mercury intrusion porosimetry.