TY - JOUR

T1 - Comparative Study of the Structural Features and Electrochemical Properties of Nitrogen-Containing Multi-Walled Carbon Nanotubes after Ion-Beam Irradiation and Hydrochloric Acid Treatment

AU - Korusenko, Petr M.

AU - Nesov, Sergey N.

AU - Iurchenkova, Anna A.

AU - Fedorovskaya, Ekaterina O.

AU - Bolotov, Valery V.

AU - Povoroznyuk, Sergey N.

AU - Smirnov, Dmitry A.

AU - Vinogradov, Alexander S.

N1 - Funding Information: Acknowledgments: The authors are grateful to the Helmholtz Zentrum Berlin für Materialien und Energie for support during NEXAFS and XPS measurements within the bilateral Russian–German Laboratory program (project No. 192-08770 ST). The authors are thankful to Yu. A. Sten’kin for the synthesis of the initial N-MWCNTs. The work was partly performed using the equipment of the resource center “VTAN” (Novosibirsk State University). Funding Information: This research was funded by the Russian Science Foundation (grant No. 21-72-10029), and partly supported within the governmental order for Omsk Scientific Center SB RAS (project registration number 121021600004-7) in terms of obtaining and studying the initial (as-prepared) nano-tubes. The authors are grateful to the Helmholtz Zentrum Berlin f?r Materialien und Energie for support during NEXAFS and XPS measurements within the bilateral Russian?German Laboratory program (project No. 192-08770 ST). The authors are thankful to Yu. A. Sten?kin for the synthesis of the initial N-MWCNTs. The work was partly performed using the equipment of the resource center ?VTAN? (Novosibirsk State University). Funding Information: Funding: This research was funded by the Russian Science Foundation (grant No. 21-72-10029), and partly supported within the governmental order for Omsk Scientific Center SB RAS (project registration number 121021600004-7) in terms of obtaining and studying the initial (as-prepared) nanotubes. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/9

Y1 - 2021/9

N2 - Using a set of microscopic, spectroscopic, and electrochemical methods, a detailed study of the interrelation between the structural and electrochemical properties of the as-prepared nitro-gen-containing multi-walled carbon nanotubes (N-MWCNTs) and their modified derivatives is car-ried out. It was found that after treatment of nanotubes with hydrochloric acid, their structure is improved by removing amorphous carbon from the outer layers of N-MWCNTs. On the contrary, ion bombardment leads to the formation of vacancy-type structural defects both on the surface and in the bulk of N-MWCNTs. It is shown that the treated nanotubes have an increased specific capacitance (up to 27 F·g−1 ) compared to the as-prepared nanotubes (13 F·g−1). This is due to an increase in the redox capacitance. It is associated with the reversible Faraday reactions with the participation of electrochemically active pyridinic and pyrrolic nitrogen inclusions and oxygen-containing functional groups (OCFG). Based on the comparison between cyclic voltammograms of N-MWCNTs treated in HCl and with an ion beam, the peaks on these curves were separated and assigned to specific nitrogen inclusions and OCFGs. It is shown that the rate of redox reactions with the participation of OCFGs is significantly higher than that of reactions with nitrogen inclusions in the pyri-dinic and pyrrolic forms. Moreover, it was established that treatment of N-MWCNTs in HCl is ac-companied by a significant increase in the activity of nitrogen centers, which, in turn, leads to an increase in the rate of redox reactions involving OCFGs. Due to the significant contribution of redox capacitance, the obtained results can be used to develop supercapacitors with increased total specific capacitance.

AB - Using a set of microscopic, spectroscopic, and electrochemical methods, a detailed study of the interrelation between the structural and electrochemical properties of the as-prepared nitro-gen-containing multi-walled carbon nanotubes (N-MWCNTs) and their modified derivatives is car-ried out. It was found that after treatment of nanotubes with hydrochloric acid, their structure is improved by removing amorphous carbon from the outer layers of N-MWCNTs. On the contrary, ion bombardment leads to the formation of vacancy-type structural defects both on the surface and in the bulk of N-MWCNTs. It is shown that the treated nanotubes have an increased specific capacitance (up to 27 F·g−1 ) compared to the as-prepared nanotubes (13 F·g−1). This is due to an increase in the redox capacitance. It is associated with the reversible Faraday reactions with the participation of electrochemically active pyridinic and pyrrolic nitrogen inclusions and oxygen-containing functional groups (OCFG). Based on the comparison between cyclic voltammograms of N-MWCNTs treated in HCl and with an ion beam, the peaks on these curves were separated and assigned to specific nitrogen inclusions and OCFGs. It is shown that the rate of redox reactions with the participation of OCFGs is significantly higher than that of reactions with nitrogen inclusions in the pyri-dinic and pyrrolic forms. Moreover, it was established that treatment of N-MWCNTs in HCl is ac-companied by a significant increase in the activity of nitrogen centers, which, in turn, leads to an increase in the rate of redox reactions involving OCFGs. Due to the significant contribution of redox capacitance, the obtained results can be used to develop supercapacitors with increased total specific capacitance.

KW - nitrogen-containing multi-walled carbon nanotubes

KW - functionalization

KW - oxygen-containing functional groups

KW - pyrrolic and pyridinic nitrogen inclusions

KW - ion beam irradiation

KW - hydrochloric acid treatment

KW - electrochemical behavior

KW - pseudocapacitance

KW - supercapacitors

KW - X-RAY PHOTOELECTRON

KW - ELECTRONIC-STRUCTURE

KW - DOPED CARBON

KW - SUPERCAPACITOR PERFORMANCE

KW - FUNCTIONAL-GROUPS

KW - CYCLIC VOLTAMMETRY

KW - HYDROXYL-GROUPS

KW - GRAPHENE OXIDE

KW - STORAGE

KW - ABSORPTION

KW - Nitrogen-containing multi-walled carbon nanotubes

KW - Supercapacitors

KW - Oxygen-containing functional groups

KW - Functionalization

KW - Pseudocapacitance

KW - Pyrrolic and pyridinic nitrogen inclusions

KW - Ion beam irradiation

KW - Electrochemical behavior

KW - Hydrochloric acid treatment

UR - http://www.scopus.com/inward/record.url?scp=85120904869&partnerID=8YFLogxK

U2 - 10.3390/nano11092163

DO - 10.3390/nano11092163

M3 - Article

C2 - 34578479

VL - 11

JO - Nanomaterials

JF - Nanomaterials

SN - 2079-4991

IS - 9

M1 - 2163

ER -