TY - JOUR

T1 - Effect of Pretreatment with Acids on the N-Functionalization of Carbon Nanofibers Using Melamine

AU - Maksimova, Tatyana A.

AU - Mishakov, Ilya V.

AU - Bauman, Yury I.

AU - Ayupov, Artem B.

AU - Mel’gunov, Maksim S.

AU - Dmitrachkov, Aleksey M.

AU - Nartova, Anna V.

AU - Stoyanovskii, Vladimir O.

AU - Vedyagin, Aleksey A.

N1 - Funding Information: This work was supported by the Ministry of Science and Higher Education of the Russian Federation (project No. AAAA-A21-121011390054-1). Publisher Copyright: © 2022 by the authors.

PY - 2022/11

Y1 - 2022/11

N2 - Nowadays, N-functionalized carbon nanomaterials attract a growing interest. The use of melamine as a functionalizing agent looks prospective from environmental and cost points of view. Moreover, the melamine molecule contains a high amount of nitrogen with an atomic ratio C/N of 1/2. In present work, the initial carbon nanofibers (CNFs) were synthesized via catalytic pyrolysis of ethylene over microdispersed Ni–Cu alloy. The CNF materials were pretreated with 12% hydrochloric acid or with a mixture of concentrated nitric and sulfuric acids, which allowed etching of the metals from the fibers and oxidizing of the fibers’ surface. Finally, the CNFs were N-functionalized via their impregnation with a melamine solution and thermolysis in an inert atmosphere. According to the microscopic data, the initial structure of the CNFs remained the same after the pretreatment and post-functionalization procedures. At the same time, the surface of the N-functionalized CNFs became more defective. The textural properties of the materials were also affected. In the case of the oxidative treatment with a mixture of acids, the highest content of the surface oxygen of 11.8% was registered by X-ray photoelectron spectroscopy. The amount of nitrogen introduced during the post-functionalization of CNFs with melamine increased from 1.4 to 4.3%. Along with this, the surface oxygen concentration diminished to 6.4%.

AB - Nowadays, N-functionalized carbon nanomaterials attract a growing interest. The use of melamine as a functionalizing agent looks prospective from environmental and cost points of view. Moreover, the melamine molecule contains a high amount of nitrogen with an atomic ratio C/N of 1/2. In present work, the initial carbon nanofibers (CNFs) were synthesized via catalytic pyrolysis of ethylene over microdispersed Ni–Cu alloy. The CNF materials were pretreated with 12% hydrochloric acid or with a mixture of concentrated nitric and sulfuric acids, which allowed etching of the metals from the fibers and oxidizing of the fibers’ surface. Finally, the CNFs were N-functionalized via their impregnation with a melamine solution and thermolysis in an inert atmosphere. According to the microscopic data, the initial structure of the CNFs remained the same after the pretreatment and post-functionalization procedures. At the same time, the surface of the N-functionalized CNFs became more defective. The textural properties of the materials were also affected. In the case of the oxidative treatment with a mixture of acids, the highest content of the surface oxygen of 11.8% was registered by X-ray photoelectron spectroscopy. The amount of nitrogen introduced during the post-functionalization of CNFs with melamine increased from 1.4 to 4.3%. Along with this, the surface oxygen concentration diminished to 6.4%.

KW - carbon nanofibers

KW - CCVD

KW - melamine

KW - N-functionalization

KW - Ni–Cu catalyst

KW - oxidative treatment

UR - http://www.scopus.com/inward/record.url?scp=85142711747&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/2cca5981-be07-33b4-af3e-9e5226d3e984/

U2 - 10.3390/ma15228239

DO - 10.3390/ma15228239

M3 - Article

C2 - 36431724

AN - SCOPUS:85142711747

VL - 15

JO - Materials

JF - Materials

SN - 1996-1944

IS - 22

M1 - 8239

ER -