RU2379228C1 - Method of filling carbon nanotubes with hydrogen - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: in the method of filling carbon nanotubes with hydrogen after undergoing thermo-chemical activation in zinc sulphide vapour, filling is carried out at 25°C for 24 hours under hydrogen pressure of 78-80 atm.

EFFECT: increased amount of hydrogen stored in nanotubes.

1 tbl

Description

The invention relates to the field of processing nanostructures.

Studies of carbon nanotubes (CNTs) as promising hydrogen storage materials show that the conditions for filling tubes with hydrogen (temperature, time, and pressure) are important factors determining the amount of hydrogen stored in CNTs. From an economic point of view, low temperatures and pressures with a relatively short filling time are advisable.

A known method of filling with hydrogen CNTs, thermochemically activated by treatment in pairs of zinc sulfide [RF Patent No. 2296046, publ. March 27, 2007, bull. 9] - prototype. The method is described in the description of the invention, in an example, and consists in filling the CNTs with hydrogen at a pressure of 100 atm at a temperature of 25 ° C for 24 hours. The parameters of this process fully comply with the criterion of economic feasibility. The disadvantage of this method is the low hydrogen content in the CNT, not exceeding 4.1% (wt.).

The objective of the present invention is to increase the amount of hydrogen stored at a temperature of 25 ° C for 24 hours in carbon nanotubes that have undergone thermochemical activation in zinc sulfide vapors.

This problem is solved in the proposed method of filling carbon nanotubes with hydrogen by carrying out the process under a pressure of 78-80 atm.

The method allows you to store in CNTs from 4.9 to 5.3% (wt.) Hydrogen. Such an amount of stored hydrogen cannot be explained by physical adsorption of hydrogen, and its chemical interaction with CNTs at room temperature is unlikely. Under the conditions of the proposed method, hydrogen clusters are supposedly formed between CNT layers that have undergone thermochemical activation in zinc sulfide vapors.

The process parameters are selected experimentally. At hydrogen pressures below 78 and above 80 atm, the amount of hydrogen stored in CNTs drops sharply, which is confirmed by the results presented in the table.

It can be assumed that at hydrogen pressures below 78 atm, the formation of hydrogen clusters does not occur or their content is small. At hydrogen pressures above 80 atm, rapid cluster destruction is likely to occur due to structural damage to the walls of CNTs, which, due to interaction with zinc sulfide vapors during thermochemical activation, have a higher content of dangling bonds in comparison with nanotubes activated by other methods or not subjected to activation.

Table No. Pressure N ₂ in the process of filling CNT, atm The amount of N ₂ stored in CNTs,% (wt.) one. thirty 0.8 ± 0.7 2. 40 1.1 ± 0.7 3. fifty 1.4 ± 0.7 four. 60 1.9 ± 0.7 5. 70 2.4 ± 0.7 6. 75 3.1 ± 0.7 7. 77 3.8 ± 0.7 8. 78 4.9 ± 0.7 9. 79 5.1 ± 0.7 10. 80 5.3 ± 0.7 eleven. 81 4.2 ± 0.7 12. 85 3.6 ± 0.7 13. 90 3.4 ± 0.7 fourteen. one hundred 3.3 ± 0.7

Example 1:

CNTs, thermochemically activated in zinc sulfide vapors, are filled with hydrogen at a pressure of 78 atm, at a temperature of 25 ° C for 24 hours. Then, the amount of hydrogen released from the CNTs when the nanotubes are heated to 300 ° C is measured by volumetric method. The resulting value is taken as the amount of hydrogen stored by CNTs during the filling process. The content of hydrogen stored in CNTs calculated from these data is 4.9 ± 0.7% (wt.).

Example 2:

CNTs, thermochemically activated in zinc sulfide vapors, are filled with hydrogen at a pressure of 79 atm, at a temperature of 25 ° C for 24 hours. Then, the amount of hydrogen released from the CNTs when the nanotubes are heated to 300 ° C is measured by volumetric method. The resulting value is taken as the amount of hydrogen stored by CNTs during the filling process. The content of hydrogen stored in CNTs calculated from these data is 5.1 ± 0.7% (wt.).

Example 3:

CNTs thermochemically activated in zinc sulfide vapors are filled with hydrogen at a pressure of 80 atm, at a temperature of 25 ° C for 24 hours. Then, the amount of hydrogen released from the CNTs when the nanotubes are heated to 300 ° C is measured by volumetric method. The resulting value is taken as the amount of hydrogen stored by CNTs during the filling process. The content of hydrogen stored in CNTs calculated from these data is 5.3 ± 0.7% (wt.).

Claims (1)

A method of filling hydrogen with carbon nanotubes that have undergone thermochemical activation in zinc sulfide vapors under a hydrogen pressure of 25 ° C for 24 hours, characterized in that the filling is carried out under a hydrogen pressure of 78-80 atm.