Fragmentation of metal(II) bis(acetylacetonate) complexes induced by slow electrons

• Janina Kopyra and
• Hassan Abdoul-Carime

Beilstein J. Nanotechnol. 2023, 14, 980–987, doi:10.3762/bjnano.14.81

• electron beam with an organometallic target (e.g., focused electron beam-induced deposition, FEBID) is a promising technique for direct 3D deposition of high-purity materials with minimum residual carbon in the product on the surface [4][5]. The FEBID precursor molecules adsorb and diffuse on the surface

• . Metal bis(acetylacetonate) complexes are of interest for many thin film fabrication techniques (e.g., chemical vapor deposition [9], atomic layer epitaxy [10], or atomic layer etching [11]) and as precursors for carbon materials, such as carbon nanotubes and carbon onion particles [12], or metal oxide

• nanocrystals [13][14]. The popularity of these compounds is related to their volatile nature, ease of preparation, and often lower air sensitivity and toxicity in comparison to organometallic compounds containing carbon–metal bonds (e.g., metallocenes). In the context of a potential use of these organometallic

Metal-organic framework-based nanomaterials for CO₂ storage: A review

• Ha Huu Do,
• Iqra Rabani and
• Hai Bang Truong

Beilstein J. Nanotechnol. 2023, 14, 964–970, doi:10.3762/bjnano.14.79

• , directly linked to the rise in global temperature, has raised significant attention. Carbon capture and storage, particularly in association with adsorbents, has occurred as a pivotal approach to address this pressing issue. Large surface area, high porosity, and abundant adsorption sites make metal

• tackle this issue is the advancement of carbon capture and storage (CCS) methods, particularly those involving highly efficient adsorbents [6][7]. The CCS process has the capability to effectively treat substantial volumes of CO2 emissions originating from conventional fossil fuel sources [8][9][10

• ]. Therefore, identification and development of durable and efficient adsorbents are critical to the successful implementation of CCS. Until now, various classes of materials have been investigated for CO2 adsorption, such as covalent organic frameworks, molecular sieves, activated carbon, and metal-organic

Low temperature atomic layer deposition of cobalt using dicobalt hexacarbonyl-1-heptyne as precursor

• Mathias Franz,
• Mahnaz Safian Jouzdani,
• Lysann Kaßner,
• Marcus Daniel,
• Frank Stahr and
• Stefan E. Schulz

Beilstein J. Nanotechnol. 2023, 14, 951–963, doi:10.3762/bjnano.14.78

• dicobalt hexacarbonyl tert-butylacetylene (CCTBA) can be used to deposit metallic cobalt in the temperature range from 125 to 200 °C [15]. As an exception, Kim et al. have reported the ALD of Co with Co2(CO)8 in the temperature range of 70 to 110 °C. However, this process resulted in a significant carbon

• overview spectrum is given in Supporting Information File 1, Figure S1. The film mainly consists of the three elements carbon (63.1 atom %), oxygen (20.8 atom %), and cobalt (16.1 atom %). The main carbon 1s feature is located at 285.0 eV binding energy (Figure 5). This is the typical value for carbon in

• alkyls [33]. It is likely that this correlates to the carbon bonded as −CH2− within the n-heptyne group of the used precursor. The second peak at 285.6 eV matches the bonding state of the terminating −CH3 groups. The third peak at 289.1 eV is likely correlated to −C=O bonds, especially originating from

Prediction of cytotoxicity of heavy metals adsorbed on nano-TiO₂ with periodic table descriptors using machine learning approaches

• Joyita Roy,
• Souvik Pore and
• Kunal Roy

Beilstein J. Nanotechnol. 2023, 14, 939–950, doi:10.3762/bjnano.14.77

• derivatives [15], 51 manufactured nanoparticles with varying core metals, coatings, and surface attachments [16], and 80 surface-modified multiwall carbon nanotubes have been reported. Another approach, namely nano-read-across (nano-RA) [17], has been used to determine the cytotoxicity of unknown

• was added to HK-2 cells in Hyclone DMEM medium supplemented with 10% fetal bovine serum (FBS) and 100 mg penicillin/streptomycin and maintained at 37 °C in the presence of 5% carbon dioxide. Nine concentrations of heavy metal salts were added to a constant amount of nano-TiO2 (25 µmol/L). The details

Upscaling the urea method synthesis of CoAl layered double hydroxides

• Camilo Jaramillo-Hernández,
• Víctor Oestreicher,
• Martín Mizrahi and
• Gonzalo Abellán

Beilstein J. Nanotechnol. 2023, 14, 927–938, doi:10.3762/bjnano.14.76

• prepared by paint spraying on carbon paper. The optimum amount of material for the measurements was calculated by the program “Hephaestus”, which is part of the Demeter package [77]. A Si(111) double-crystal monochromator was used to obtain a monochromatic incident beam, and the intensities of incident and

• corresponding structure. Microscopy Sample preparation The dried solids were suspended in ethanol and drop cast onto Au TEM grids covered with a lacy carbon film, and the solvent was left to evaporate. SEM samples were prepared from the same solution after 5 min of ultrasonication. The sonicated suspension was

Ni, Co, Zn, and Cu metal-organic framework-based nanomaterials for electrochemical reduction of CO₂: A review

• Ha Huu Do and
• Hai Bang Truong

Beilstein J. Nanotechnol. 2023, 14, 904–911, doi:10.3762/bjnano.14.74

• of Technology, Van Lang University, Ho Chi Minh City, Vietnam 10.3762/bjnano.14.74 Abstract The combustion of fossil fuels has resulted in the amplification of the greenhouse effect, primarily through the release of a substantial quantity of carbon dioxide into the atmosphere. The imperative pursuit

• CO2 conversion. Finally, a meticulous discourse encompasses the challenges encountered and the prospects envisioned for the advancement of MOF-based nanomaterials in the realm of electrochemical reduction of CO2. Keywords: carbon capture; CO2 reduction; electrocatalysis; metal-organic frameworks

• ; nanomaterials; Introduction The emission of carbon dioxide resulting from the utilization of fossil fuels has been identified as a primary cause of the greenhouse effect, ultimately contributing to the severity of climate change [1]. To mitigate these detrimental consequences, numerous strategies have been

Two-dimensional molecular networks at the solid/liquid interface and the role of alkyl chains in their building blocks

• Suyi Liu,
• Yasuo Norikane and
• Yoshihiro Kikkawa

Beilstein J. Nanotechnol. 2023, 14, 872–892, doi:10.3762/bjnano.14.72

• ][54][55]. Recently, dispersion-corrected DFT calculations have quantitatively revealed the interactions between n-alkanes and circumcoronene as models of molecular adsorption on HOPG [47]. As the number of carbon atoms in the n-alkane increased, the adsorption energy increased by −1.85 kcal/mol per

• ) exhibited different 2D structures in which the core unit of PBTP was surrounded by branched alkyl chains (Figure 9c,d). When PBTP was substituted with eight butyl ester groups at the 3, 4, 9, and 10 carbon positions of the two perylene motifs (Scheme 7c), porous honeycomb networks were created (Figure 9e,f

• patterns (7 × 10−4 M, Figure 10e,f) at the HOPG/TCB interface. By reducing the number of alkyl chains, the DBA derivative can adopt various conformations on the surface, forming polymorphic structures. 5 Odd–even effect In addition to simple changes in the intermolecular distance, the number of carbon

N-Heterocyclic carbene-based gold etchants

• Robert B. Chevalier,
• Justin Pantano,
• Matthew K. Kiesewetter and
• Jason R. Dwyer

Beilstein J. Nanotechnol. 2023, 14, 865–871, doi:10.3762/bjnano.14.71

• water and carbon dioxide so that there was no need for a strong base for deprotonation or for air-free conditions [13][14]. Camden and co-workers have used CO2 adducts of benzimidazolium to produce NHC films by melting the solid CO2 adduct directly onto a gold surface under vacuum. They have also

Biomimetics on the micro- and nanoscale – The 25th anniversary of the lotus effect

• Matthias Mail,
• Kerstin Koch,
• Thomas Speck,
• William M. Megill and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2023, 14, 850–856, doi:10.3762/bjnano.14.69

• their model for “Atmospheric water harvesting using functionalized carbon nanocones”. The challenge of harvesting water directly from air of varying humidity is a tantalizing one. There are several biological examples in both the animal and plant kingdoms which could serve as archetypes for

• dehumidifiers or water purifiers. The authors here present a model based on a carbon nanotube structure that might finally provide a route to the breakthrough in this field. Their archetype, the Namibian desert beetle, uses a geometric separation of hydrophilic and hydrophobic regions to harvest and drive water

• along its body. The authors built on this inspiration to develop carbon nanotube cones which similarly separate the regions. Their model predicts the specific geometry and surface properties that will be required to create a low-pressure system for harvesting water vapour. Rebora et al. [19], in the

Ultralow-energy amorphization of contaminated silicon samples investigated by molecular dynamics

• Grégoire R. N. Defoort-Levkov,
• Alan Bahm and
• Patrick Philipp

Beilstein J. Nanotechnol. 2023, 14, 834–849, doi:10.3762/bjnano.14.68

• planned to reach down to 50 eV, which would be correspondingly surface sensitive, in the near future. In the two above cases, contaminations in the experimental chamber play an important role during the sputtering processes. Typical contaminations are (in the order of frequency) water, nitrogen, carbon

• and carbonated components that can be found in the atmosphere [22][23][24], and residuals from past experiments in the chamber, which can include silicon, carbon, or any type of particles that were sputtered previously and adsorbed on the walls of the sample chamber [24][25]. The work in this paper

• renewal of the water layer. Future simulations could include other types of contaminants, such as nitrogen or carbon-containing impurities that are very often found in instrument chambers, and the renewal of the contamination layer during the sputtering process. Representations of the contaminated sample

A wearable nanoscale heart sound sensor based on P(VDF-TrFE)/ZnO/GR and its application in cardiac disease detection

• Yi Luo,
• Jian Liu,
• Jiachang Zhang,
• Yu Xiao,
• Ying Wu and
• Zhidong Zhao

Beilstein J. Nanotechnol. 2023, 14, 819–833, doi:10.3762/bjnano.14.67

• bottle was sealed and placed in a shaking mixer and shaken for 3 h. Next, ZnO nanoparticles (Shanghai Keyan Industrial Co., Ltd., particle size 3 ± 5 nm, content ≥99.8%) and GR filler (Shenzhen Turing Evolution Technology Co., Ltd., carbon content 98%, average diameter/thickness ratio = 9500) were added

Carboxylic acids and light interact to affect nanoceria stability and dissolution in acidic aqueous environments

• Matthew L. Hancock,
• Eric A. Grulke and
• Robert A. Yokel

Beilstein J. Nanotechnol. 2023, 14, 762–780, doi:10.3762/bjnano.14.63

• formation of cerium coordination complexes on the ceria nanoparticle surface that inhibit agglomeration. Key functional groups of carboxylic acids that prevented nanoceria agglomeration were identified. A long carbon chain backbone containing a carboxylic acid group geminal to a hydroxy group in addition to

• agglomerates on the edges of the lacey carbon film are nanoceria. The presence of β-hydroxybutyric acid appeared to reduce the overall number of nanoceria particles from week 0 through week 2, similar to citric acid. However, by week 4, large micrometer-sized agglomerates were detected, made up of hundreds of

• isocitric acid all contain at least one more carboxylic acid group (citric and isocitric acid contain two additional groups). The same is true for tartaric, tartronic, and dihydroxymalonic acid; however, the carbon chain is shorter for these molecules and does not contain any CH2 groups, which may prevent

In situ magnesiothermic reduction synthesis of a Ge@C composite for high-performance lithium-ion batterie anodes

• Ha Tran Huu,
• Ngoc Phi Nguyen,
• Vuong Hoang Ngo,
• Huy Hoang Luc,
• Minh Kha Le,
• Minh Thu Nguyen,
• My Loan Phung Le,
• Hye Rim Kim,
• In Young Kim,
• Sung Jin Kim,
• Van Man Tran and
• Vien Vo

Beilstein J. Nanotechnol. 2023, 14, 751–761, doi:10.3762/bjnano.14.62

• performance of the electrode (432.3 mAh·g−1 at a specific current of 5000 mA·g−1) are attributed to the enhancement in distribution and chemical contact between Ge nanoparticles and the biomass-based carbon matrix. A comparison with other synthesis routes has been conducted to demonstrate the effectiveness of

• performance of Ge-based anodes, a carbon matrix is the most popular choice to disperse nanoparticles, avoiding their aggregation and reducing the internal stress induced by volume variation, because of its flexible structure and high conductivity [30][31][32]. In our recent study, the combination of Ge

• nanoparticles and a carbon matrix using a hydrothermal route has been reported, and the enhancement in the electrochemical performance of Ge@C electrodes was demonstrated [33]. In this work, a one-pot synthesis route has been followed to prepare a Ge@C composite using an in situ magnesiothermic reduction of

Control of morphology and crystallinity of CNTs in flame synthesis with one-dimensional reaction zone

• Muhammad Hilmi Ibrahim,
• Norikhwan Hamzah,
• Mohd Zamri Mohd Yusop,
• Ni Luh Wulan Septiani and
• Mohd Fairus Mohd Yasin

Beilstein J. Nanotechnol. 2023, 14, 741–750, doi:10.3762/bjnano.14.61

• Malaysia, 81310 Johor Bahru, Malaysia Advanced Membrane Technology Research Center, Universiti Teknologi Malaysia, 81310 Johor Bahru, Malaysia National Research and Innovation Agency, Indonesia 10.3762/bjnano.14.61 Abstract The growth of carbon nanotubes (CNTs) in a flame requires conditions that are

• CNT functionalization for energy storage, nanosensor, and nanocomposite applications, where diameter and crystallinity are influential properties that govern the overall performance of the components. Keywords: carbon nanotubes; crystallinity; flame synthesis; morphology; one-dimensional flame

• ; synthesis control; Introduction Carbon nanotubes have been a research topic for a few decades since their discovery by Iijima in 1991 [1]. The CNT structure enables remarkable mechanical, electrical, and thermal properties. Studies of CNT syntheses using different methods yielding nanotubes with varying

Nanomaterials for photocatalysis and applications in environmental remediation and renewable energy

• Viet Van Pham and
• Wee-Jun Ong

Beilstein J. Nanotechnol. 2023, 14, 722–724, doi:10.3762/bjnano.14.58

• fuels generates harmful emissions to the environment, such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), nitric oxide and nitrogen dioxide (together termed NOx), and fluorinated gases (e.g., hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride) which are currently considered

• appropriate for treating pollutants, even in atmospheric conditions [9][10][11]. Moreover, the photocatalysis method is also a potential solution for environmental remediation, carbon emission reduction, and renewable energy production [12][13][14]. Combining photocatalysts and sunlight irradiation is a

• development of advanced materials based on semiconductors (i.e., carbon-modified hexagonal boron nitride (MBN), MgO@g-C3N4, and TiO2@MWCNTs) have indicated a highly efficient photocatalytic performance for phenol removal using a low-power visible LED light source. For NO degradation, a visible light source

A graphene quantum dots–glassy carbon electrode-based electrochemical sensor for monitoring malathion

• Sanju Tanwar,
• Aditi Sharma and
• Dhirendra Mathur

Beilstein J. Nanotechnol. 2023, 14, 701–710, doi:10.3762/bjnano.14.56

• diffraction were used to characterize the morphological and structural properties of GQDs. An electrochemical sensor was developed by drop casting GQDs on a glassy carbon electrode (GCE). The sensor detects the organophosphate pesticide malathion in a selective and sensitive manner. Using cyclic voltammetry

• -area to volume ratio to provide enhanced analyte interaction with the sensing surface [14]. Carbon-based nanomaterials and nanocomposites are being investigated for the electrochemical detection of a variety of pesticides, including organophosphates, organochlorines, and carbamates [15][16][17]. The

• lowers the detection limit [18]. In an effort to combine the properties of carbon dots and graphene, graphene quantum dots (GQDs) with a size smaller than 100 nm and only a few layers of graphene (3 to 10 layers) have been developed as a new class of carbon nanomaterials [19]. Scientists have explored

Metal-organic framework-based nanomaterials as opto-electrochemical sensors for the detection of antibiotics and hormones: A review

• Akeem Adeyemi Oladipo,
• Saba Derakhshan Oskouei and
• Mustafa Gazi

Beilstein J. Nanotechnol. 2023, 14, 631–673, doi:10.3762/bjnano.14.52

• researchers have published a number of nanomaterial-based (quantum dots, carbon-based, and metal-based) sensors for the detection of various analytes [1][2][7][9][27][28][29][30][31][32][33][34][35][36][37][38]. A review paper that offers a comprehensive analysis of current developments based on metal-organic

• , which lowers their electrochemical detection performance [64]. Researchers have focused on various research efforts to improve the conductivity and amplify the electrical signals of MOFs by combining them with other highly conductive materials (such as carbon materials, metal nanoparticles, or metal

• oxides) [63][64][65][66][67][68][69]. This is motivated by their large surface area, which can facilitate the loading of nanoparticles. Additionally, MOFs have been converted into their electrochemically active derivatives, such as mesoporous carbon composites and porous metal oxides, to achieve an

Titania nanoparticles for photocatalytic degradation of ethanol under simulated solar light

• Evghenii Goncearenco,
• Iuliana P. Morjan,
• Claudiu Teodor Fleaca,
• Florian Dumitrache,
• Elena Dutu,
• Monica Scarisoreanu,
• Valentin Serban Teodorescu,
• Alexandra Sandulescu,
• Crina Anastasescu and
• Ioan Balint

Beilstein J. Nanotechnol. 2023, 14, 616–630, doi:10.3762/bjnano.14.51

• described as: The raw TiO2 powders contain some carbon (from the decomposition of the ethylene sensitizer) and chlorine impurities, whose amount it is greatly diminished by calcination in air at 450 °C for 5 h. To certify this, a composition investigation by energy-dispersive X-ray spectroscopy (EDS) has

• spectral alignment of the binding energy (BE) scale was referenced to adventitious carbon at 284.8 eV [40][41]. Figure 4a shows the full survey scans of TO-250-a, TO-850-b, and commercial TiO2 (Degussa P25) samples, indicating the presence of the expected elements Ti, O, and C. The high-resolution XPS

• spectra of the C 1s, O 1s, and Ti 2p regions of TO-250-a, TO-850-b, and P25 are indicated in Figure 4b–d. The carbon region consists of three singlets with maxima located at 284.8, 286.1, and 289 eV (see Figure 4b). The highest peak located at 284.8 eV originates from the C=C bond, followed by the

Transferability of interatomic potentials for silicene

• Marcin Maździarz

Beilstein J. Nanotechnol. 2023, 14, 574–585, doi:10.3762/bjnano.14.48

• graphene has also sparked interest in other non-carbon 2D materials [1][2]. One of such materials is 2D silicon, called silicene [3][4]. Using first-principles methods with current computer resources enables us to model structures up to about a few hundred atoms. For larger systems, approximate methods are

ZnO-decorated SiC@C hybrids with strong electromagnetic absorption

• Liqun Duan,
• Zhiqian Yang,
• Yilu Xia,
• Xiaoqing Dai,
• Jian’an Wu and
• Minqian Sun

Beilstein J. Nanotechnol. 2023, 14, 565–573, doi:10.3762/bjnano.14.47

• that crystalline ZnO particles adhere to the surface of amorphous carbon, and the ZnO content increases as a function of a dosage of ZnNO3·6H2O. The as-prepared SiC@C-ZnO hybrids exhibit effective electromagnetic absorption, which is related to a synergy effect of different dielectric loss processes

• mm). The excellent properties of the materials suggest great prospect as electromagnetic absorbers. Keywords: carbon; dielectric; electromagnetic absorption; SiC nanowires; ZnO; Introduction With increasing functionality of electronic devices, the widening of the working frequency bands, and the

• ]. Nevertheless, the EM absorption of most SiC-based absorbers with heterostructures is far from satisfactory [21][22][23]. In our previous work, SiC@C nanowires have been successfully obtained by surface carbonization of SiC nanowires [24]. Carbon materials are prone to bond with other dielectric or magnetic

Carbon nanotube-cellulose ink for rapid solvent identification

• Tiago Amarante,
• Thiago H. R. Cunha,
• Claudio Laudares,
• Ana P. M. Barboza,
• Ana Carolina dos Santos,
• Cíntia L. Pereira,
• Vinicius Ornelas,
• Bernardo R. A. Neves,
• André S. Ferlauto and
• Rodrigo G. Lacerda

Beilstein J. Nanotechnol. 2023, 14, 535–543, doi:10.3762/bjnano.14.44

• Federal do ABC, Santo André - CEP 09210-580, Brazil 10.3762/bjnano.14.44 Abstract In this work, a conductive ink based on microfibrillated cellulose (MFC) and multiwalled carbon nanotubes (MWCNTs) was used to produce transducers for rapid liquid identification. The transducers are simple resistive

• devices that can be easily fabricated by scalable printing techniques. We monitored the electrical response due to the interaction between a given liquid with the carbon nanotube–cellulose film over time. Using principal component analysis of the electrical response, we were able to extract robust data to

• rapid, inexpensive, and robust liquid analysis and identification. Keywords: carbon nanotube; electronic tongue; fibrillated cellulose; liquid sensor; Introduction The development of a new generation of smart sensors that allow for the monitoring of industrial processes in real time and for wearable

On the use of Raman spectroscopy to characterize mass-produced graphene nanoplatelets

• Keith R. Paton,
• Konstantinos Despotelis,
• Naresh Kumar,
• Piers Turner and
• Andrew J. Pollard

Beilstein J. Nanotechnol. 2023, 14, 509–521, doi:10.3762/bjnano.14.42

• particular the absence of graphite or nanoscale graphite. It is important to recall that graphene has been defined as a “single layer of carbon atoms with each atom bound to three neighbours in a honeycomb structure” with materials with more than one layer defined as “few-layer graphene” or “graphene

Conjugated photothermal materials and structure design for solar steam generation

• Chia-Yang Lin and
• Tsuyoshi Michinobu

Beilstein J. Nanotechnol. 2023, 14, 454–466, doi:10.3762/bjnano.14.36

• . Photothermal materials (PTMs) applied to SSG include metallic materials, semiconductors, carbon-based materials, and conjugated organic materials [1][2][3][4]. Compared to metallic and inorganic PTMs, π-conjugated organic PTMs have advantages, such as a greater light absorption, easier synthesis, and

• can be predicted by density functional theory (DFT) calculations of the conjugated structures. This is an advantage over other carbon materials, even if they are of the same chemical composition [18][19][20][21][22]. We review the recent progress in the material development of conjugated solar

Molecular nanoarchitectonics: unification of nanotechnology and molecular/materials science

• Katsuhiko Ariga

Beilstein J. Nanotechnol. 2023, 14, 434–453, doi:10.3762/bjnano.14.35

• conventional analytical methods. It is also possible to reveal how functional sites such as catalysts are incorporated into the immobilization process. For example, an atomistic understanding of the structure of heterogeneous catalysts consisting of MoO2 complexes on carbon nanohorns has been reported [43

• , some of the recent examples are presented. Molecular synthesis of unusual structures can lead to novel functional structures. Segawa's recent review describes the synthesis of nonplanar structures by molecular nanoarchitectonics of sp2-hybridized carbon atoms [92]. The flexibility of the structure

• . Unlike conventional solution synthesis, low-temperature local probe chemistry allows for a free control of the radical state. This kind of local probe chemistry as a synthesis technique opens up the possibility of nanoarchitectonics synthesis of carbon nanomaterials. The tip-induced addition of single

Evaluation of electrosynthesized reduced graphene oxide–Ni/Fe/Co-based (oxy)hydroxide catalysts towards the oxygen evolution reaction

• Karolina Cysewska,
• Marcin Łapiński,
• Marcin Zając,
• Jakub Karczewski,
• Piotr Jasiński and
• Sebastian Molin

Beilstein J. Nanotechnol. 2023, 14, 420–433, doi:10.3762/bjnano.14.34

• different kinds of conductive carbon materials [14][15][16][17][18]. Recently, graphene (Gr)/graphene oxide (GO) has attracted the attention of many researchers due to its high surface area, significant chemical stability, high electrical conductivity, and high mechanical strength [12][19]. Combining a

• and/or GO. For example, Wu et al. [13] chemically fabricated metal alloys and their oxides (NiCo, CoFe) with nitrogen-doped graphene (N-rGO/NiCo-NiO-CoO, N-rGO/CoFe-Co2FeO4) on a glassy carbon electrode (GCE). The N-rGO/NiCo-NiO-CoO and N-rGO/CoFe-Co2FeO4 catalysts revealed an OER overpotential (η) of

• Figure 3a–d shows the X-ray absorption spectra (XAS) of the L3 edge of nickel (a), iron (b), cobalt (c), and carbon (d) in the studied catalysts. The appearance of a shoulder peak at the L3 edge of the nickel (Figure 3a) at 855 eV indicates the presence of oxides in the structure of the catalysts (Ni in