Nanocomposites and nanomaterials
Features of effect of cold plasma treatment on hydrogen sorption by graphene oxide

R.M. Basnukaeva1, A.V. Dolbin1, M.V. Khlistyuck1, V.B. Esel'son1, 
V.G. Gavrilko1, N.A.Vinnikov1, O. L. Rezinkin2 and M. M. Rezinkina2

1 B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkov 61103, Ukraine.
E-mail:razeta9556@gmail.com 
2 National Technical University “Kharkiv Polytechnic Institute”, 2 Kirpichov Street, Kharkov, 61102, Ukraine
Graphene is a two-dimensional allotropic modification of carbon formed by a monolayer of sp²-hybridized carbon atoms joined into a hexagonal crystal lattice. Graphene has remarkable properties, such as high thermal conductivity, excellent mechanical properties, excellent electrical properties and is a good sorbent. It was previously established that the treatment of carbon nanostructures with cold plasma, obtained using a high-frequency pulsed gas discharge under reduced pressure, significantly improves the sorption characteristics of nanostructures [1]. In this work, the original thermally reduced graphene oxide (TRGO) was obtained from graphite powder using a modified Hammers method. The treatment of the TRGO sample with a pulsed high-frequency (HF) discharge was carried out in a hydrogen atmosphere at room temperature and a pressure about P ≈ 2 Torr. The electric capacity of the discharge circuit was 0.1 mF, the frequency of the discharge circuit was f ≈ 1.1 MHz, the amplitude value of the voltage was – up to 800 V, the pulse repetition rate was 5 Hz, and the distance between the electrodes was about 2 mm. The sample was located directly on a high-voltage electrode having a special site [1]. The total sample processing time was 48 hours. Studies of the processes of hydrogen sorption-desorption with initial and modified pulsed HF discharge in a hydrogen atmosphere with samples of thermally reduced graphene oxide (TRGO and MTRGO) were performed in the temperature range from 9 K to 293 K using a laboratory bench, the design and principle of operation of which are described in detail in [2]. The treatment with a pulsed discharge in a hydrogen atmosphere significantly (1.5 times) increased the sorption capacity of thermally reduced graphene oxide with respect to physically sorbed hydrogen. It can be assumed that such increasing is due to changes in the distance between adjacent carbon surfaces in the MTRGO graphene-plane packages due to the chemical addition of ionized hydrogen when treating an HF gas discharge.
1. A.V. Dolbin, N.A. Vinnikov, V.B. Esel'son, V.G. Gavrilko, R.M. Basnukaeva, M.V. Khlistyuck, A.I. Prokhvatilov, V.V. Meleshko, O.L. Rezinkin, and Rezinkina M.M. Effect of cold plasma treatment on the hydrogen sorption by carbon nanostructures // Fiz. Nizk. Temp. – 2018. – 44. – P. 1033
2 A.V. Dolbin, M.V. Khlistyuck, V.B. Esel'son, V.G. Gavrilko, N.A. Vinnikov, R.M. Basnukaeva, I. Maluenda, W.K. Maser and Benito A.M. The effect of the thermal reduction temperature on the structure and sorption capacity of reduced graphene oxide materials // Applied Surface Science – 2016. – 361. – P.213