A brief bibliometric analysis of Web of Science publications on “Carbon” topic for 2019–2020

Chigarev B.N.

Actual Problems of Oil and Gas. Iss. 2(33) 2021 http://oilgasjournal.ru

DOI 10.29222/ipng.2078-5712.2021-33.art6 UDС [303.6+303.7]:001.8

A brief bibliometric analysis of Web of Science publications on "Carbon" topic for 2019-2020

B.N. Chigarev

Oil and Gas Research Institute, Russian Academy of Sciences, Moscow E-mail: bchigarev@ipng.ru

Abstract. A brief bibliometric analysis of 5,000 most cited scientific publications presented in the Web of Science database on the "Carbon" topic for 2019-2020 is done. It is shown that the world's leading scientific centers of China, the United States, India, South Korea, Japan and Germany, as well as the Russian Academy of Sciences are involved in research on this topic. The following areas of scientific research were dominant: materials science, physical chemistry, nanotechnology, engineering chemistry, applied physics, energy, electrochemistry, ecology, condensed matter physics.

The clustering method based on the co-occurrence of the Author Keywords and the Keywords Plus of the Web of Science system revealed six areas of research: 1. catalysis, hydrogen production, carbon materials doped with nitrogen; 2. graphite/graphene-based energy storage systems; 3. sensors and emissions based on carbon quantum dots; 4. nanocomposites and their physical properties; 5. energy consumption and climate change; 6. adsorption and organic pollutants.

The author assumes the high potential of research on the co-production of hydrogen and graphite, which may combine the interests of hydrogen energy development and production of new materials.

Keywords: bibliometric analysis, Web of Science, scientometrics, carbon, graphene, hydrogen, catalysis, nanocomposites, energy storages.

Citation: Chigarev B.N. A brief bibliometric analysis of Web of Science publications on "Carbon" topic for 2019-2020 // Actual Problems of Oil and Gas. 2021. Iss. 2(33). P. 76-100. https://doi.org/10.29222/ ipng.2078-5712.2021-33.art6

Introduction

The Paris Climate Agreement aims to keep global warming well below two degrees Celsius, which imposes limits on greenhouse gas emissions1.

On the other hand, the United Nations Sustainable Development Goal 7 (SDG7) implies universal access to affordable, reliable, sustainable and modern energy sources2. The energy sector (electricity, heat and transport) is responsible for 73.2% of greenhouse gas emissions3.

A compromise in solving these problems can be achieved by co-producing hydrogen and carbon from fossil energy sources, which does not

1 The Paris Agreement. https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement

2 Goal 7: Affordable and clean energy. https://www.un.org/sustainabledevelopment/energy/

3 Sector by sector: where do global greenhouse gas emissions come from?

https://ourworldindata.org/emissions-by-sector

require the utilization of carbon dioxide (CO2), especially from natural gas.

For example, the leading corporations of Russia's fuel and energy sector consider methane pyrolysis technology a promising way to enable the production of hydrogen and pure carbon4.

While the subject of hydrogen economy is well researched [1-3], the "production of materials based on carbon" direction is underrepresented in oil and gas studies. Thus, the query "carbon" in OnePetro, the online library of technical literature for the oil and gas industry, gets 17,327(2,702) publications for 2011-2020, while the query "carbon dioxide" OR "carbon capture" gets 7,080(1,175) papers, and the queries "carbon nanotube" and "graphene" get only 205 and 249(42) results respectively.

4 Russia in the global hydrogen race. https://www.swp-

berlin.org/en/publication/russia-in-the-global-hydrogen-

race/

This is an open access article under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/)

The number in parentheses refers to the articles in peer-reviewed journals. For comparison, in the Web of Science Core Collection, the queries: TOPIC: ("carbon nanotube") and TOPIC: (graphene) get 125,350 and 217,689 results for the given years respectively.

To reduce the biases associated with a single abstract database and a broad query, TOPIC, I present for comparison the data of The Lens

database by the narrow queries: "Filters: Year Published = (2011-2020) Keyword = (Carbon Nanotubes)" obtains 2,624 records, while "Keyword = (Graphene)" obtains 5,783 records for the same period. To illustrate the topics of publications, I present graphs of the data in the "Fields of Study" and "Subject" fields for each of the queries (Fig. 1, 2).

2,407 2,201 2,053 1,206 5,398

Carbon nanotube Chemical engineering Chemistry Composite material Graphene

7,168 1,909 3,339 995 1,015

Materials science Nanocomposite Nanotechnology Optoelectronics Oxide

Fig. 1. Distribution of publication topics for the query "Keyword = (Carbon Nanotubes)" by the fields:

a - "Fields of Study", b - "Subject"

1,094 1,131 532 573 5,176

Chemical engineering Chemistry Composite material Electrode Graphene

4,404 517 2,257 828 862

Materials science Nanocomposite Nanotechnology Optoelectronics Oxide

Fig. 2. Distribution of publication topics for the query "Keyword = (Graphene)" by the fields:

a - "Fields of Study", b - "Subject"

In any data slice, the dominant topics are materials science, graphene, carbon nanotubes,

nanotechnology, condensed state physics and composites.

a

b

a

b

Such a huge number of peer-reviewed publications on the above queries aligns well with industry needs; for example, the carbon fiber market is expected to grow from $4.7 billion in

2019 to $13.3 billion by 2029, at an average annual growth rate of 11.0% over the period from 2019 to 20 295.

The global graphene market was estimated at $78.7 million in 2019 and is expected to grow at a compound annual growth rate of 38.7% from

2020 to 20 276.

For the Russian fuel and energy sector, the rapidly developing market for carbon-based materials can be of great interest, so it is advisable to analyze the picture of scientific research on this topic.

Materials

To build an overall picture of carbon-related scientific publications and to reduce selection biases, bibliometric data from the Web of Science (WoS) reference database were retrieved by the most general query:

TITLE: (carbon) and Timespan: 2019-2020 and Indexes: SCI-EXPANDED, ESCI.

A total of 58,924 results were obtained at the time of the query (28.10.2020). For further bibliometric analysis, I selected 5,000 most cited publications. At the same time, the bulk of the publications - 4,598 articles - falls on 2019, the papers of 2020 are not indexed in full, so the citation can only be evaluated later.

The choice of the base query was derived from the analysis of the test query data. The total number of publications indexed in the WoS for 2011-2020 for the query "carbon* OR graphene*" was:

5Global carbon fiber market size.

https://www.whatech.com/markets-research/materials-chemicals/705441-carbon-fiber-market-by-raw-material-pan-pitch-rayon-fiber-type-virgin-recycled-product-type-modulus-application-composite-non-composite-end-use-industry

6Graphene market size.

https://www.grandviewresearch.com/industry-analysis/graphene-industry

- 1,125,785 publications when searching by all fields of the database;

- 1,074,048 documents when searching by the titles, Author Keywords and Keywords Plus (the index terms generated by the WoS by in-depth analysis of the references of the articles).

- 381,641 publications when narrowing the search to the presence of "carbon* OR graphene*" only in the titles.

By removing "graphene*" from the query, I reduced the focus of interest on a specific type of material, by limiting the time interval to 20192020, I focused the interest on recent publications, which corresponds to the main objective of this paper: to analyze the current landscape of scientific publications on the topic "Carbon".

The data from The Lens platform were additionally used to demonstrate the independence of the obtained results from the chosen abstract database.

Methods

Following the aim of this study - to build the overall picture of carbon-related scientific publications - I used only bibliometric methods for assessing the co-occurrence of the sum of Author Keywords and Keywords Plus (clustering), as well as some data from the "Analysis of results" section of the WoS. For keyword clustering, I used the VOSviewer scientometric and bibliometric software [4, 5]. The total number of unique keywords in 5,000 publications were 18,985, with 975 words occurring more than nine times. The parameter of the minimum number of words in the cluster was chosen to be 100. The stability of clustering was checked by changing this parameter by ±20%. This resulted in the identification of six clusters.

Keywords and other terms in the tables are given as they appear in the bibliometric data, enabling to use them in a further selection of materials by subject specialists.

For each cluster, I give examples of references to highly cited publications that illustrate the subject of this cluster well.

General bibliometric data on 58,924 publications

The processing of 58,924 bibliometric data gathered by the query: "TITLE: (carbon) and

Distribution of publication ac

Timespan: 2019-2020 and Indexes: SCI-EXPANDED, ESCI" revealed the distribution of publication activity by country and source of funding (Table 1).

Table 1

by country and funding sources

Countries Records Funding Agencies Records

Peoples R China 26,488 National Natural Science Foundation of China NSFC 18,356

USA 8,167 Fundamental Research Funds for the Central Universities 2,938

India 3,610 National Key Research and Development Program of China 1,688

South Korea 2,985 China Postdoctoral Science Foundation 1,679

Japan 2,778 National Science Foundation NSF 1,569

Germany 2,663 National Key R&D Program of China 1,234

Iran 2,213 Ministry of Education Culture Sports Science and Technology Japan MEXT 1,032

England 2,183 European Union EU 922

Australia 2,155 Japan Society for the Promotion of Science 880

Canada 1,590 United States Department of Energy DOE 865

Russia 1,575 Natural Science Foundation of Jiangsu Province 798

France 1,555 China Scholarship Council 790

Spain 1,411 National Council for Scientific and Technological Development CNPG 703

Italy 1,263 Australian Research Council 641

Brazil 1,247 Chinese Academy of Sciences 641

Saudi Arabia 950 CAPES 633

Turkey 910 German Research Foundation DFG 626

Taiwan 897 Natural Science Foundation of Shandong Province 615

Malaysia 852 Natural Sciences and Engineering Research Council of Canada 595

Poland 838 Grants-in-Aid for Scientific Research (KAKENHI) 586

Table 1 indicates that the dominance of carbon-related publications from China correlates well with the list of funders, which are also predominantly Chinese. India has good publication activity, largely due to extensive collaboration with other countries. The US and European researchers also rely on good funding: National Science Foundation; European Union; United States Department of Energy (DOE); German Research Foundation. Research in Japan is supported by Ministry of Education, Culture, Sports Science and Technology Japan (MEXT) and Grants-in-Aid for Scientific Research (KAKENHI).

The fact that Russia occupies an intermediate position between Canada and France indicates that Russian researchers pay considerable attention to the topic in question. Two factors

should be taken into account: less involvement of Russian research institutions in international cooperation compared to the institutions of China, the United States and Europe, and the fact that a significant part of the research results is published in Russian-language journals that are not indexed in the Web of Science.

Worth noting is the high publication activity of Iran, which is under stronger sanctions than Russia but is better represented in the publications in highly ranked journals.

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Most frequent are the publications in these seven languages (of the total number of 58,924): English (58,147); Chinese (333); Spanish (77); Korean (76); Russian (67); German (66); Japanese (44).

Further, I analyzed the distribution of publication activity by the WoS categories and journal titles (Table 2). Table 2 indicates that the WoS categories are dominated by sections related to materials science, chemistry, condensed state physics, metallurgy, polymers, nanotechnology and energy. The journal titles in the second column of the table agree well with the WoS categories, with journals publishing articles on various topics

Distribution of publication activity

in chemistry and materials science predominating. Of particular note is the International Journal of Hydrogen Energy (h-index=202), which is the official publication of the International Association for Hydrogen Energy. Sections on "hydrogen fuel cells", "electrolysis of water to produce hydrogen" and "hydrogen storage using nanomaterials" all involve the development of new materials based on various forms of graphite.

Table 2

WoS categories and journal titles

WoS categories Records Source titles Records

Materials Science Multidisciplinary 14,171 Carbon (Q1) 974

Chemistry Physical 10,243 Chemical Engineering Journal (Q1) 737

Chemistry Multidisciplinary 7,808 Applied Surface Science (Q1) 732

Environmental Sciences 6,499 Electrochimica Acta (Q1) 722

Nanoscience Nanotechnology 5,323 ACS Applied Materials Interfaces (Q1) 693

Engineering Chemical 5,186 Journal of Cleaner Production (Q1) 672

Physics Applied 5,030 Science of the Total Environment (Q1) 645

Energy Fuels 4,841 Journal of Alloys and Compounds (Q1) 639

Electrochemistry 3,856 Journal of Materials Chemistry A (Q1) 622

Engineering Environmental 3,088 RSC Advances (Q2) 552

Physics Condensed Matter 3,023 ACS Sustainable Chemistry Engineering (Q1) 487

Chemistry Analytical 2,514 Abstracts of Papers of the American Chemical Society 485

Green Sustainable Science Technology 2,302 International Journal of Hydrogen Energy (Q2) 451

Metallurgy Metallurgical Engineering 1,885 Environmental Science and Pollution Research (Q2) 443

Polymer Science 1,822 Scientific Reports (Q1) 441

Multidisciplinary Sciences 1,632 Journal of Colloid and Interface Science (Q1) 439

Materials Science Coatings Films 1,589 Materials (Q2) 403

Materials Science Composites 1,566 Journal of Power Sources (Q1) 378

Geosciences Multidisciplinary 1,112 Nanoscale (Q1) 354

Soil Science 1,059 Nanomaterials (Q1) 337

Note: Journal quartile membership was dete highest score in the WoS.

Ten organizations/affiliations with the highest publication activity are: Chinese Academy of Sciences (3897); University of Chinese Academy of Sciences CAS (1,394); Centre national de la recherche scientifique (1,070); Russian Academy of Sciences (827); University of California System (800); United States Department of Energy (794); Indian Institute of Technology System (748); Tsinghua University (671); University of Science Technology of China (574); Helmholtz Association (569).

by the Journal Citation Reports category with the

Bibliometric analysis of the 5,000 most highly cited articles revealing the dominant areas of research

Research topics are described well both by Author Keywords and by Keywords Plus generated by the WoS system (Table 3). Table 3 indicates that the most frequent are the keywords associated with graphene, carbon nanomaterials, graphene oxide, carbon nanotubes, nanocomposites and graphene quantum dots.

Table 3

The 40 most frequent keywords in 5,000 highly cited publications 2019-2020 (data retrieved 28.10.2020)

Keyword Occurrence Keyword Occurrence

performance** 804 catalysts 209

graphene* 766 carbon nanotubes* 198

nanoparticles* 669 oxide 195

nanosheets* 500 oxygen reduction reaction 188

nitrogen 361 removal 178

adsorption 328 supercapacitor*** 178

porous carbon* 318 storage*** 175

water 316 degradation 170

nanotubes* 315 reduced graphene oxide 165

composite 314 metal-organic frameworks 163

composites 284 energy 162

activated carbon 278 oxidation 162

graphene oxide* 258 biomass 161

facile synthesis 254 energy-storage*** 161

nanocomposites* 251 quantum dots* 161

efficient 242 nanocomposite* 156

fabrication 238 graphene quantum dots* 152

reduction 227 high-performance** 150

electrode 217 oxygen reduction 144

electrodes 216 behavior 143

Note: the single (*), double (**) and triple (***) asterisks indicate terms that might be conventionally assigned to the same cluster. For example: supercapacitor***, storage***, energy-storage***.

The keyword "performance" comes first in terms of frequency; the examples of phrases with it in the full texts are: catalytic performance, highperformance lithium-sulfur batteries, electromechanical performance, electrocatalytic performance, photocatalytic performance, electrochemical performance, storage performance, high-performance anode materials, high-performance composites. This indicates the high importance of the examined subject for applied research, which is also confirmed by such keywords as: manufacturing, supercapacitor, storage, degradation, metal-organic framework, energy accumulation.

Clustering of keywords based on their co-occurrence in the 5,000 most cited publications

For a detailed study of the "Carbon" topic, I used the clustering of keywords based on their cooccurrence in the 5,000 most cited publications.

VOSviewer, a program designed to build and visualize bibliometric data networks, was used for keyword clustering.

Keyword clustering (Author + KeyWords Plus) was performed under the following conditions: out of 18,985 keywords, 975 keywords were selected that occurred more than nine times, while each cluster included at least 100 keywords.

Six clusters were obtained:

1. catalysis, hydrogen-production, nitrogen-doped carbon;

2. graphite/graphene-based energy storage systems;

3. sensors and emissions based on carbon quantum dots;

4. nanocomposites and their physical properties;

5. energy consumption and climate change;

6. adsorption and organic pollutants.

Their main features are presented below in tables and graphs. The stability of clustering was checked by changing of the minimum number of keywords in the cluster by ±20%.

In compiling the summary tables for each of the six clusters, 40 of the most frequent keywords were selected and used to describe the cluster theme.

The tables contain the following fields: label (keyword name), keyword occurrence and the average citation of the publications in which this keyword appears.

It should be noted that the average citation of a keyword is determined by the average citation of the articles whose entries contain this term in the Author keywords and Keywords Plus fields. This value can be retrieved from the GML files generated by VOSViewer.

In addition to the tables, graphs of the relationships between terms are presented for the two most frequent terms in each cluster. Such data presentation makes it possible to demonstrate the relationship between terms not only within a cluster but also between clusters.

The results of the bibliometric analysis for the first cluster are presented in Table 4 and Fig. 3 and 4.

Table 4

The 40 most frequent keywords within the Cluster 1 and the average citations of publications associated with a keyword

Label Occurrence Average citations Label Occurrence Average citations

nitrogenA 361 23.2 electrocatalysis* 88 26.0

water 316 22.5 iron 86 20.9

facile synthesis 254 23.5 oxygen** 85 23.0

efficient 242 23.3 co2 reduction 84 25.7

reduction 227 21.2 electrocatalyst* 82 23.0

catalysts* 209 22.9 hydrogen evolution** reaction 79 25.3

oxygen reduction** reaction 188 26.4 active-sites 77 25.9

degradation 170 20.0 sulfur 75 21.7

metal-organic frameworks 163 25.0 TIO2 74 17.7

oxidation** 162 20.6 construction 71 24.9

oxygen reduction** 144 25.1 dioxide 69 21.4

catalyst* 140 20.6 oxygen evolution reaction 67 24.3

electrocatalysts* 137 27.3 CO 66 19.7

evolution 136 24.8 nitrogen-doped carbonA 64 23.0

highly efficient 132 23.0 doped carbon 62 23.8

conversion 130 21.0 hydrogen** 62 20.7

hydrogen evolution** 130 30.5 carbon nitrideA 58 27.3

metal-organic framework 127 20.8 g-C3N4 nanosheetsA 58 22.9

photocatalysis* 123 26.0 graphitic carbon nitrideA 58 23.5

g-C3N4A 103 22.6 N-doped carbonA 58 22.5

Note: Contextually related terms are marked by the symbols * and **. Nitrogen-related terms are marked by the symbol A.

This cluster can be conditionally labelled "Catalysis, hydrogen-production, nitrogen-doped carbon". Several categories of keywords correspond with this label: electrocatalysis, photocatalysis, hydrogen evolution, oxygen evolution reaction, as well as the most cited publications mentioning electro- and

photocatalysis, hydrogen evolution [6, 7]; the keywords related to carbon nitride (carbon nitride, graphitic carbon nitride, nanosheets, g-C3N4) and the corresponding publications [8-11]. Noteworthy is the frequent mention of nitrogen-doped carbon, which is considered to be a promising type of cathode catalyst [12-15].

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Fig. 3. Cluster 1. The main links of the term "nitrogen" with the other terms

nanocomposites

Fig. 4. Cluster 1. The main links of the term "water" with the other terms

The results of the bibliometric analysis for the second cluster are presented in Table 5 and Fig. 5 and 6.

Table 5

The 40 most frequent keywords within the Cluster 2 and the average citations of publications associated with a keyword

Label Occurrence Average citations Label Occurrence Average citations

graphene* 766 22.0 high-capacity** 107 23.8

nanosheets* 500 23.3 lithium** 107 23.2

porous carbon* 318 23.9 hybrid 98 22.4

nanotubes* 315 21.3 nanostructures* 94 23.6

composite 314 21.6 carbon 89 23.0

electrode** 217 22.5 nanospheres* 88 24.6

electrodes** 216 23.8 anode materials** 82 25.1

oxide 195 20.6 batteries** 80 24.5

supercapacitor** 178 19.1 capacity** 80 22.3

storage** 175 21.8 arrays 79 22.8

reduced graphene oxide 165 22.7 anode material** 78 23.0

energy-storage** 161 23.5 spheres 77 19.6

high-performance 150 23.8 capacitance** 74 20.8

anode** 132 22.6 nanocrystals 73 23.1

cathode** 130 21.0 sodium-ion batteries 73 26.6

electrochemical performance** 128 22.4 doped graphene* 69 27.7

supercapacitors** 127 18.4 graphite 69 22.4

electrode materials** 114 20.3 hierarchical porous carbon 67 19.0

nanofibers* 114 24.8 lithium-ion** 64 23.5

microspheres 112 27.4 shell 64 22.2

Note: Contextually related terms are marked by the symbols * and

The conditional name for the cluster is "Graphite/graphene-based energy storage systems". Corresponding keywords: graphene, porous carbon, nanotubes, nanostructures, nano-

particles, nanocrystals, doped graphene, electrode materials, anode, cathode, electrochemical characteristics, supercapacitors, high capacity, lithium, sodium-ion and lithium-ion batteries.

Fig. 5. Cluster 2. The main links of the term "graphene" with the other terms

Fig. 6. Cluster 2. The main links of the term "nanosheets" with the other terms

This cluster is represented by the publications [16-21].

The results of the bibliometric analysis for the third cluster are presented in Table 6 and Fig. 7 and 8.

Table 6

The 40 most frequent keywords within the Cluster 3 and the average citations of publications associated with a keyword

Label Occurrence Average citations Label Occurrence Average citations

nanoparticles 669 20.4 chemistry 48 19.3

graphene oxide 258 23.2 mild-steel 47 16.5

quantum dots* 161 20.8 green 46 20.5

nanocomposite 156 19.9 emission 45 16.2

graphene quantum dots* 152 21.5 functionalization 44 20.0

carbon dots* 130 19.4 ions 44 18.6

sensor** 119 17.1 biosensor** 41 19.1

nanodots* 115 18.2 luminescence** 41 19.5

green synthesis 83 20.5 hydrogen-peroxide 40 18.4

photoluminescence** 79 18.2 electrochemical sensor** 37 16.3

sensitive detection** 73 19.6 ascorbic-acid 34 19.1

one-step synthesis 67 31.0 glucose 33 17.9

acid 66 18.2 voltammetric determination** 33 17.6

fluorescence** 65 17.7 probe** 32 17.3

hydrothermal synthesis 63 20.0 label-free detection 31 34.6

one-pot synthesis 62 28.4 dopamine 30 16.8

carbon quantum dots* 58 23.3 extraction 30 16.9

gold nanoparticles 58 21.2 sensors** 30 17.9

selective detection** 58 18.3 complexes 29 17.0

nanomaterials 51 19.5 derivatives 29 15.7

Note: Contextually related terms are marked by the symbols * and **.

The conditional name for the cluster is "Sensors and emissions based on carbon quantum dots". Corresponding keywords: graphene/carbon quantum dots, nanodots,

sensors, selective detection, biosensor, electrochemical sensors, voltammetric determination, probe, label-free detection, fluorescence, luminescence.

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Fig. 7. Cluster 3. The main links of the term "nanoparticles" with the other terms

ne caps itor:

efiergyistor^ge* de®,ty j electrOTfiemiiial perfc

Fig. 8. Cluster 3. The main links of the term "graphene oxide" with the other terms

This cluster is represented by the publications [22-27].

The results of the bibliometric analysis for the fourth cluster are presented in Table 7 and Fig. 9 and 10.

Table 7

The 40 most frequent keywords within the Cluster 4 and the average citations of publications associated with a keyword

Label Occurrence Average citations Label Occurrence Average citations

performance 804 21.1 electrical-conductivity** 45 23.1

composites* 284 21.4 microstructure** 43 19.9

nanocomposites* 251 22.0 morphology** 43 18.6

fabrication 238 20.3 strength** 43 17.4

carbon nanotubes* 198 20.9 layer 42 20.3

behavior** 143 17.8 mechanical properties** 41 20.3

mechanical-properties** 126 19.1 networks 41 23.0

design** 121 21.5 dispersion** 40 16.3

stability** 116 18.9 microwave absorption** 39 29.1

surface 114 17.9 deposition 36 20.4

temperature** 88 22.2 particles 35 18.1

carbon nanotube* 78 16.3 thermal-conductivity** 34 22.4

lightweight 72 25.5 polymers* 33 25.8

enhancement 70 22.9 network 31 19.5

films 68 22.6 polymer composites* 31 18.9

conductivity 58 20.1 resistance** 31 19.4

fibers 54 24.3 thin-films 31 24.0

foam 53 20.2 matrix 30 22.0

polymer 50 19.4 surface modification** 30 25.0

absorption 48 21.0 carbon fiber* 28 17.4

Note: Contextually related terms are marked by the symbols * and :

The conditional name for the cluster is "Nanocomposites and their physical properties". Corresponding keywords: composites, nanocomposites, carbon nanotubes, polymer composites, thin-films, carbon fiber, electrical properties, elastic properties, mechanical

properties, thermal-properties, stability, surface, temperature, light weight, conductivity, absorption, electrical conductivity, microstructure, strength, electromagnetic-wave absorption, resistance, surface modification, fabrication, design.

Fig. 9. Cluster 4. The main links of the term "performance" with the other terms

ligh^ight

Fig. 10. Cluster 4. The main links of the term "composites" with the other terms This cluster is represented by the publications [28-32].

The results of the bibliometric analysis for the fifth cluster are presented in Table 8 and Fig. 11 and 12.

Table 8

The 40 most frequent keywords within the Cluster 5 and the average citations of publications associated with a keyword

Label Occurrence Average citations Label Occurrence Average citations

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energy* 162 21.2 matter 34 19.0

CO2 emissions** 115 22.4 system 34 17.8

CO2** 84 19.6 greenhouse-gas** emissions 33 15.9

growth 75 21.3 gas** 31 16.4

model 69 17.6 sequestration 31 16.2

energy-consumption* 54 22.3 carbon dioxide** 29 23.2

efficiency* 53 18.6 management 29 16.4

climate-change** 49 21.1 emissions** 28 17.1

optimization* 49 17.3 organic-matter 28 17.1

impact** 48 16.6 pH 28 19.4

China** 46 19.3 black carbon 27 16.0

decomposition 43 18.7 financial development 26 26.2

transport* 40 21.1 methane** 26 16.2

dynamics 39 15.9 optical-properties 25 16.7

dioxide emissions** 38 25.1 urbanization 25 19.4

mechanisms 36 22.0 aerogels 24 22.3

renewable energy* 36 24.6 climate change** 24 16.5

environmental kuznets curve** 35 29.2 life-cycle assessment 23 18.7

carbon emissions** 34 22.4 recovery 23 20.0

economic-growth* 34 19.4 systems 23 14.5

Note: Contextually related terms are marked by the symbols * and **.

The conditional name of the cluster is "Energy consumption and climate change". Corresponding keywords: energy consumption, efficiency, optimization, transport, renewable

energy, management, financial development, economic growth, urbanization, life-cycle assessment, CO2 emissions, environmental Kuznets curve, climate change.

Fig. 11. Cluster 5. The main links of the term "energy" with the other terms

Fig. 12. Cluster 5. The main links of the term "CO2 emissions" with the other terms This cluster is represented by the publications [33-37].

The results of the bibliometric analysis for the sixth cluster are presented in Table 9 and Fig. 13 and 14.

Table 9

The 40 most frequent keywords within the Cluster 6 and the average citations of publications associated with a keyword

Label Occurrence Average citations Label Occurrence Average citations

1 2 3 4 5 6

nitrogenA 361 23.2 electrocatalysis* 88 26.0

water 316 22.5 iron 86 20.9

facile synthesis 254 23.5 oxygen** 85 23.0

efficient 242 23.3 CO2 reduction 84 25.7

reduction 227 21.2 electrocatalyst* 82 23.0

catalysts* 209 22.9 hydrogen evolution** reaction 79 25.3

oxygen reduction** reaction 188 26.4 active-sites 77 25.9

degradation 170 20.0 sulfur 75 21.7

metal-organic frameworks 163 25.0 TIO2 74 17.7

oxidation** 162 20.6 construction 71 24.9

Table 9 continued

1 2 3 4 5 6

oxygen reduction** 144 25.1 dioxide 69 21.4

catalyst* 140 20.6 oxygen evolution reaction 67 24.3

electrocatalysts* 137 27.3 CO 66 19.7

evolution 136 24.8 nitrogen-doped carbonA 64 23.0

highly efficient 132 23.0 doped carbon 62 23.8

conversion 130 21.0 hydrogen** 62 20.7

hydrogen evolution** 130 30.5 carbon nitrideA 58 27.3

metal-organic framework 127 20.8 g-C3N4 nanosheetsA 58 22.9

photocatalysis* 123 26.0 graphitic carbon nitrideA 58 23.5

g-C3N4A 103 22.6 N-doped carbonA 58 22.5

Note: Contextually related terms are marked by the symbols * and **. Nitrogen-related terms are marked by the symbol A.

cor^^les

Fig. 13. Cluster 6. The main links of the term "adsorption" with the other terms

Fig. 14. Cluster 6. The main links of the term "activated carbon" with the other terms This cluster is represented by the publications [38-43].

The conditional name of this cluster is "Adsorption and organic pollutants". Corresponding keywords: adsorption, activated carbon, mesoporous carbon, adsorbent, separation, sorption, chemical activation, high-surface-area, biomass, organic pollutants, waste-water treatment.

Conclusions

1. The brief bibliometric analysis of scientific publications on "Carbon" topic indicated a high level of applied research in the following Web of Science categories: Materials Science (Ceramics, Composites); Physical Chemistry; Condensed Matter Physics; Polymer Science; Nanoscience and Nanotechnology; Metallurgy and Metallurgical Engineering; Energy and Fuels. This knowledge can provide a foundation for the development of technology and the production of carbon-based materials.

2. The wide involvement of the world's leading economies in research on this topic was revealed. The good positions of Russia and the Russian Academy of Sciences in the research on carbon-based materials, the importance of the fuel and energy sector for the economy and the necessity of its transformation to achieve the United Nations Sustainable Development Goals make the subject of combining the tasks of hydrogen energy and carbon-based materials

production relevant for applied and fundamental science.

3. The clustering method based on the cooccurrence of keywords yielded the six areas of research, which can be conventionally labelled as:

1) catalysis, hydrogen-production, nitrogen-doped carbon;

2) graphite/graphene-based energy storage systems;

3) sensors and emissions based on carbon quantum dots;

4) nanocomposites and their physical properties;

5) energy consumption and climate change;

6) adsorption and organic pollutants.

The topic of hydrogen energy is well traced in the studies related to carbon-based materials.

The research area of hydrogen and graphite co-production is highly relevant, since it combines the needs of hydrogen energy development, graphite-based materials production (particularly for renewable energy purposes) and the objectives of CO2 emission reduction [44-50].

Especially important are the studies on the production of hydrogen by thermochemical pyrolysis of CH4 using a carbon catalyst and solar energy, which produces hydrogen and black carbon without generating CO2 [51-52].

Статья написана в рамках выполнения государственного задания (тема«Фундаментальный базис инновационных технологий нефтяной и газовой промышленности (фундаментальные, поисковые и прикладные исследования)», № АААА-А19-119013190038-2).

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DOI 10.29222/ipng.2078-5712.2021-33.art6

УДК [303.6+303.7]:001.8

Краткий библиометрический анализ публикаций Web of Science по теме «Углерод» за 2019-2020 гг.

Б.Н. Чигарев

Институт проблем нефти и газа РАН, г. Москва E-mail: bchigarev@ipng.ru

Аннотация. Дан краткий библиометрический анализ 5000 наиболее цитируемых научных публикаций, представленных в базе Web of Science по теме «Углерод» за 2019-2020 гг. Показано, что в исследования по данной тематике вовлечены ведущие мировые научные центры Китая, США, Индии, Южной Кореи, Японии, Германии, а также Российская академия наук. Доминировали следующие направления научных исследований: материаловедение, физическая химия, нанотехнологии, инженерная химия, прикладная физика, энергетика, электрохимия, экология, физика конденсированного состояния.

Методом кластеризации на основе совместной встречаемости ключевых слов авторов и системы Web of Science выявлено шесть направлений исследований: 1. катализ, получение водорода, углеродные материалы, легированные азотом; 2. накопители энергии на основе графита/графена; 3. сенсоры и излучатели на основе углеродных квантовых точек; 4. нанокомпозиты и их физические свойства; 5. потребление энергии и изменение климата; 6. адсорбция и органические загрязнители.

Выдвинуто предположение о перспективности исследований по совместному производству водорода и графита, которые могут объединить интересы развития водородной энергетики и производства новых материалов.

Ключевые слова: библиометрический анализ, Web of Science, наукометрия, углерод, графен, водород, катализ, нанокомпозиты, накопители энергии.

Для цитирования: Чигарев Б.Н. Краткий библиометрический анализ публикаций Web of Science по теме «Углерод» за 2019-2020 гг. // Актуальные проблемы нефти и газа. 2021. Вып. 2(33). С. 76-100. https://doi.org/10.29222/ipng.2078-5712.2021-33.art6

Литература

1. Staffell I., Scamman D., Velazquez Abad A. et al. The role of hydrogen and fuel cells in the global energy system // Energy & Environmental Science. 2019. Vol. 12, No. 2. P. 463-491. https://doi.org/10.1039/c8ee01157e

2. The future of hydrogen. Report prepared by the IEA for the G20, Japan. 2019. 203 p. https://www.iea.org/reports/the-future-of-hydrogen (Дата обращения 27.05.2021).

3. The hydrogen economy - a path towards low carbon development. SKOLKOVO Energy Centre, Moscow School of Management SKOLKOVO. 2019. 62 p. https://energy.skolkovo.ru/downloads/ documents/SEneC/Research/SKOLKOVO_EneC_Hydrogen-economy_Eng.pdf (Дата обращения 27.05.2021).

4. van Eck N.J., Waltman L. Software survey: VOSviewer, a computer program for bibliometric mapping // Scientometrics. 2010. Vol. 84, No. 2. P. 523-538. https://doi.org/10.1007/s11192-009-0146-3

5. Perianes-Rodriguez A., Waltman L., van Eck N.J. Constructing bibliometric networks: a comparison between full and fractional counting // Journal of Informetrics. 2016. Vol. 10, No. 4. P. 11781195. https://doi.org/10.1016/jjoi.2016.10.006

96

6. Zhu J., Hu L., Zhao P. et al. Recent advances in electrocatalytic hydrogen evolution using nanoparticles // Chemical Reviews. 2020. Vol. 120, No. 2. P. 851-918. https://doi.org/10.1021/ acs.chemrev.9b00248

7. Abdelhamid H.N. A review on hydrogen generation from the hydrolysis of sodium borohydride // International Journal of Hydrogen Energy. 2021. Vol. 46, No, 1. P. 726-765. https://doi.org/10.1016/ j.ijhydene.2020.09.186

8. Cao S., Low J., Yu J., Jaroniec M. Polymeric Photocatalysts Based on Graphitic Carbon Nitride // Advanced Materials. 2015. Vol. 27, No. 13. P. 2150-2176. https://doi.org/10.1002/adma.201500033

9. Ong W.-J., Tan L.-L., Ng Y.H. et al. Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesis and environmental remediation: are we a step closer to achieving sustainability? // Chemical Reviews. 2016. Vol. 116, No. 12. P. 7159-7329. https://doi.org/10.1021/acs.chemrev.6b00075

10. Orooji Y., Ghanbari M., Amiri O., Salavati-Niasari M. Facile fabrication of silver iodide/graphitic carbon nitride nanocomposites by notable photo-catalytic performance through sunlight and antimicrobial activity // Journal of Hazardous Materials. 2020. Vol. 389. P. 122079. https://doi.org/10.1016/j .jhazmat.2020.122079

11. Wang Q., Domen K. Particulate photocatalysts for light-driven water splitting: mechanisms, challenges, and design strategies // Chemical Reviews. 2020. Vol. 120, No. 2. P. 919-985. https://doi.org/10.1021/acs.chemrev.9b00201

12. Li Z., Ji S., Liu Y., Cao X. et al. Well-Defined materials for heterogeneous catalysis: from nanoparticles to isolated single-atom sites // Chemical Reviews. 2020. Vol. 120, No. 2. P. 623-682. https://doi.org/10.1021/acs.chemrev.9b00311

13. Liu P., Gao S., Wang Y., Huang Y. et al. Carbon nanocages with N-doped carbon inner shell and Co/N-doped carbon outer shell as electromagnetic wave absorption materials // Chemical Engineering Journal. 2020. Vol. 381. P. 122653. https://doi.org/10.1016/j.cej.2019.122653

14. Wang H., Maiyalagan T., Wang X. Review on recent progress in nitrogen-doped graphene: synthesis, characterization, and its potential applications // ACS Catalysis. 2012. Vol. 2, No. 5. P. 781-794. https://doi.org/10.1021/cs200652y

15. Wang Y., Ding B., Guo D., et al. A novel way to synthesize nitrogen and oxygen co-doped porous carbon for high performance supercapacitors // Microporous and Mesoporous Materials. 2019. Vol. 282. P. 114-120. https://doi.org/10.1016/j.micromeso.2019.03.031

16. Abdel Maksoud, M.I.A., Fahim, R.A., Shalan, A.E. et al. Advanced materials and technologies for supercapacitors used in energy conversion and storage: a review // Environmental Chemistry Letters. 2020. Vol. 19, No. 1. P. 375-439. https://doi.org/10.1007/s10311-020-01075-w

17. Pandolfo A.G., Hollenkamp A.F. Carbon properties and their role in supercapacitors // Journal of Power Sources. 2006. Vol. 157, No. 1. P. 11-27. https://doi.org/10.1016/jjpowsour.2006.02.065

18. Yuan C., Wu H.B., Xie Y., Lou X.W.D. Mixed transition-metal oxides: design, synthesis, and energy-related applications // Angewandte Chemie International Edition. 2014. Vol. 53, No. 6. P. 1488-1504. https://doi.org/10.1002/anie.201303971

19. Zhang L.L., Zhao X.S. Carbon-based materials as supercapacitor electrodes // Chemical Society Reviews. 2009. Vol. 38, No. 9. P. 2520-2531. https://doi.org/10.1039/b813846j

20. Korkmaz S., Kariper I.A. Graphene and graphene oxide based aerogels: Synthesis, characteristics and supercapacitor applications // Journal of Energy Storage. 2020. Vol. 27. P. 101038. https://doi.org/10.1016/j.est.2019.101038

21. Li H., Liang J. Recent development of printed micro-supercapacitors: printable materials, printing technologies, and perspectives // Advanced Materials. 2020. Vol. 32, No. 3. P. 1805864. https://doi.org/10.1002/adma.201805864

22. Ahmadian-Fard-Fini S., Ghanbari D., Amiri O., Salavati-Niasari M. Electro-spinning of cellulose acetate nanofibers/Fe/carbon dot as photoluminescence sensor for mercury (II) and lead (II) ions // Carbohydrate Polymers. 2020. Vol. 229. P. 115428. https://doi.org/10.1016/j.carbpol.2019.115428

23. Qiao G., Liu L., Hao X. et al. Signal transduction from small particles: sulfur nanodots featuring mercury sensing, cell entry mechanism and in vitro tracking performance // Chemical Engineering Journal. 2020. Vol. 382. P. 122907. https://doi.org/10.1016/j.cej.2019.122907

24. Shen J., Zhu Y., Yang X. et al. Graphene quantum dots: emergent nanolights for bioimaging, sensors, catalysis and photovoltaic devices // Chemical Communications. 2012. Vol. 48, No. 31. P. 36863699. https://doi.org/10.1039/c2cc00110a

25. Wang Y., Hu A. Carbon quantum dots: synthesis, properties and applications // Journal of Materials Chemistry C. 2014. Vol. 2, No. 34. P. 6921-6939. https://doi.org/10.1039/c4tc00988f

26. Wu S., Min H., Shi W., Cheng P. Multicenter metal-organic framework-based ratiometric fluorescent sensors // Advanced Materials. 2020. Vol. 32, No. 3. P. 1805871. https://doi.org/10.1002/adma.201805871

27. Zhu S., Meng Q., Wang L. et al. Highly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging // Angewandte Chemie International Edition. 2013. Vol. 52, No. 14. P. 3953-3957. https://doi.org/10.1002/anie.201300519

28. Huang Z.-M., Zhang Y.-Z., Kotaki M., Ramakrishna S. A review on polymer nanofibers by electrospinning and their applications in nanocomposites // Composites Science and Technology. 2003. Vol. 63, No. 15. P.2223-2253. https://doi.org/10.1016/S0266-3538(03)00178-7

29. Liang C., Qiu H., Song P. et al. Ultra-light MXene aerogel/wood-derived porous carbon composites with wall-like "mortar/brick" structures for electromagnetic interference shielding // Science Bulletin. 2020. Vol. 65, No. 8. P. 616-622. https://doi.org/10.1016/j.scib.2020.02.009