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US 2026/0242252 A1Published application
Method for forming a metal free catalyst by pyrolysis
AssigneeKing Fahd University of Petroleum and Minerals
InventorsMahmoud Atef ABDULHAMID, Zainah Ali ALDHAWI
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Abstract
A method of dye degradation includes contacting a metal-free catalyst with a dye solution in a reaction chamber. The metal-free catalyst includes a carbonized polyimide (PI) material including reacted units of a 4,4′-(hexafluoroisopropylidene) phthalic anhydride and reacted units of a 3,3′-dimethyl-naphthridine. The dye solution includes methylene blue (MB). The method further includes irradiating the reaction chamber with light and degrading dye in the dye solution.
Claims16
1-4. (canceled)
5:
- The method of claim 7, wherein the metal-free catalyst is porous having an average pore diameter of 100 to 700 nanometers (nm).
6:
- The method of claim 7, wherein the metal-free catalyst is porous having a total pore volume of 0.2 to 0.4 cubic centimeters per gram (cm3/g).
7:
- A method for forming a metal-free catalyst, comprising:
- pyrolyzing a film including reacted units of 4,4′-(hexafluoroisopropylidene) diphthalic anhydride and 3,3′-dimethyl-naphthridine at a temperature of 500 to 1,200 degrees Celsius (° C.), to form porous fibers that has a BET surface area of 540 to 740 m2/g, a Langmuir surface area of 800 to 1050 m2/g, and a total pore volume of 0.28 to 0.37 cm3/g.
8:
- The method of claim 7, wherein pyrolyzing is at a temperature of 580 to 620° C., to form porous fibers that has a BET surface area of 570 to 580 m2/g, a Langmuir surface area of 800 to 830 m2/g, and a total pore volume of 0.3 to 0.32 cm3/g.
9:
- The method of claim 7, wherein pyrolyzing is at a temperature of 780 to 820° C., to form porous fibers that has a BET surface area of 590 to 600 m2/g, a Langmuir surface area of 825 to 835 m2/g, and a total pore volume of 0.28 to 0.3 cm3/g.
10:
- The method of claim 7, wherein pyrolyzing is at a temperature of 980 to 1020° C., to form porous fibers that has a BET surface area of 720 to 740 m2/g, a Langmuir surface area of 1040 to 1050 m2/g, and a total pore volume of 0.35 to 0.37 cm3/g.
11:
- The method of claim 7, wherein the metal-free catalyst has a bandgap value of 2.5 to 3.5 electron volts (eV).
12:
- The method of claim 7, wherein the metal-free catalyst has an adsorption capacity (Qads) of 3 to 10 milligrams of dye per gram of the metal-free catalyst (mg/g).
13:
- The method of claim 7, wherein the metal-free catalyst has a degradation rate of MB of 0.001 to 0.012 per minute (min−1).
14-15. (canceled)
16:
- The method of claim 7, further comprising:
- heating 4,4′-(hexafluoroisopropylidene) diphthalic anhydride and 3,3′-dimethyl-naphthridine in m-cresol with an isoquinoline under nitrogen to form a polyimide solution;
- adding an alcohol to the polyimide solution to form a precipitate;
- washing and drying the precipitate at a temperature of 100 to 200° C. for 20 to 28 hours (h) to form a polymer;
- and
- carbonizing the polymer at a temperature of 500 to 1200° C. for 0.5 to 2 h to form the metal-free catalyst.
3 more elements
17:
- The method of claim 16, wherein the polymer has a number-average molecular weight (Mn) of 66,000 to 70,000 grams per mole (g/mol).
18:
- The method of claim 16, wherein the polymer has a molecular weight (Mw) of 82,000 to 86,000 g/mol.
19:
- The method of claim 10, wherein a signal of carbon intensity for the porous fibers is 3 to 5 times greater compared to a signal of carbon intensity for the film including reacted units of 4,4′-(hexafluoroisopropylidene) diphthalic anhydride and 3,3′-dimethyl-naphthridine that has not been pyrolyzed based on energy dispersive X-ray (EDX) analysis.
(canceled)
Dependencies are inferred from the claim text.