TY - JOUR

T1 - Methodology and results of studying the states of hydrogen in graphene structures

AU - Nechaev, Yu S.

AU - Cheretaeva, A. O.

AU - Kostikova, E. K.

AU - Shurygina, N. A.

AU - Denisov, E. A.

AU - Davydov, S. Yu

N1 - Publisher Copyright: © 2021 Taylor & Francis Group, LLC.

PY - 2021/9/30

Y1 - 2021/9/30

N2 - In this work, an effective methodology of analysis of thermal desorption spectra (TDS) of hydrogen in carbon materials was further developed and applied. The methodology makes it possible, from TDS data of one heating rate, to determine the activation energies and pre-exponential factors of the rate constants of desorption processes. The TDS data of Rajasekaran et al. for hydrogenated epitaxial graphenes with a diamond-like structure (as in graphane) were analyzed. Some new information was obtained about the states of hydrogen in such unusual structures. It was shown that about half of the hydrogen contained in the samples is localized in the interfacial regions (between graphene and the substrate), while the desorption of such hydrogen is limited by diffusion (with three activation energies (34 kJ/mol(H2), 45 kJ/mol(H2), and 68 kJ/mol(H2)) of hydrogen molecules in these regions to the lateral surfaces of the samples. It was also shown that the rest of the hydrogen is localized on the top surface of the samples, while desorption of hydrogen atoms occurs with two activation energies and frequency factors (174 kJ/mol(H), 2 × 1013 s−1, and 256 kJ/mol(H), 3 × 1018 s−1); the obtained quantities are comparable to the related characteristics for graphane.

AB - In this work, an effective methodology of analysis of thermal desorption spectra (TDS) of hydrogen in carbon materials was further developed and applied. The methodology makes it possible, from TDS data of one heating rate, to determine the activation energies and pre-exponential factors of the rate constants of desorption processes. The TDS data of Rajasekaran et al. for hydrogenated epitaxial graphenes with a diamond-like structure (as in graphane) were analyzed. Some new information was obtained about the states of hydrogen in such unusual structures. It was shown that about half of the hydrogen contained in the samples is localized in the interfacial regions (between graphene and the substrate), while the desorption of such hydrogen is limited by diffusion (with three activation energies (34 kJ/mol(H2), 45 kJ/mol(H2), and 68 kJ/mol(H2)) of hydrogen molecules in these regions to the lateral surfaces of the samples. It was also shown that the rest of the hydrogen is localized on the top surface of the samples, while desorption of hydrogen atoms occurs with two activation energies and frequency factors (174 kJ/mol(H), 2 × 1013 s−1, and 256 kJ/mol(H), 3 × 1018 s−1); the obtained quantities are comparable to the related characteristics for graphane.

KW - activation energies

KW - analysis of hydrogen thermal desorption data

KW - diamond-like structures (as in graphane)

KW - frequency factors

KW - Hydrogenated few (1 and 4) layer epitaxial graphenes

KW - STORAGE

KW - THERMAL-DESORPTION

KW - ELECTRONS

KW - MODEL

UR - http://www.scopus.com/inward/record.url?scp=85116197356&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/4454f9ee-3fe7-379e-9dde-660d8b17d1ef/

U2 - 10.1080/1536383x.2021.1984900

DO - 10.1080/1536383x.2021.1984900

M3 - Article

AN - SCOPUS:85116197356

JO - Fullerenes Nanotubes and Carbon Nanostructures

JF - Fullerenes Nanotubes and Carbon Nanostructures

SN - 1536-383X

ER -