Featured paper: Nanostructured catalysts for renewable energy production.

Transmission electron microscopy image of electrocatalyst material: metallic nanoparticles encapsulated in carbon layers.
Transmission electron microscopy image of electrocatalyst material: metallic nanoparticles encapsulated in carbon layers.

Research carried out at the São Carlos Institute of Chemistry at the University of São Paulo (IQSC-USP) resulted in a nanostructured material that works as a catalyst for electrochemical reactions (electrocatalyst) that are fundamental in some renewable energy generation systems. As it combines efficiency and low cost, the new material would be an alternative to the catalysts traditionally used in these reactions, which are based on elements of the group of precious metals, such as platinum, which are scarce and expensive.

The developed material, which, with the naked eye, has the appearance of a black powder, is hybrid and nanostructured. It consists of nanoparticles from 10 to 50 nm, composed of an iron, cobalt and nickel alloy (three relatively abundant and cheap elements), inserted in layers of carbon doped with nitrogen.

Recently reported in the Journal of Materials Chemistry A, the study presents a very simple process to obtain this material with the necessary stability for electrocatalysis applications. The method consists of preparing a water solution with iron, cobalt and nickel salts and adding organic compounds capable of binding metal ions (so-called ligands). The reaction between metals and ligands generates structures known as MOFs (metal-organic frameworks). Eventually, the obtained MOFs are submitted to high temperature (900 ° C) to obtain the final material.

“We have come up with a unique straightforward yet effective strategy for synthesis of an efficient electrocatalyst that is cheap and quite active in diver’s energy conversion reactions and could have impact in new generation energy related technologies,” says Mohmmad Khalid, a postdoctoral fellow at the Electrochemistry Group at IQSC-USP and corresponding author of the article with Professor Hamilton Varela (IQSC-USP).

The article also reports the tests carried out at the laboratories of the Electrochemistry Group at IQSC-USP to assess the performance of the nanostructured material in some applications related to sustainable energy generation, such as the division of the water molecule (hydrolysis). This process is the cleanest way to obtain hydrogen, currently considered the most promising non-fossil fuel. However, without the participation of good electrocatalysts, hydrolysis is very slow and consumes a lot of electricity. “Our nanostructured catalyst in overall water splitting impeccably works for decomposing apart the water molecules for the generation of hydrogen at applying very low potential compare to several previously reported nonprecious electrocatalysts,” says Khalid.

The nanostructured material also showed very good results as a catalyst for ethanol oxidation. This reaction is carried out on direct ethanol fuel cells to obtain electrical energy from the chemical energy of ethanol (renewable fuel with Brazil as the second largest producer in the world). “Thus, the catalyst showed its potential not only to generate hydrogen, but also for fuel cell applications,” says Khalid.

Overcoming the challenges

The work began in 2017, with a research project coordinated by Professor Hamilton Brandão Varela de Albuquerque, with the participation of postdoctoral fellow Mohmmad Khalid. According to Khalid, the final objective of the study was to find a cheap and stable electrocatalyst for the process of dividing the water molecule.

The main problems the researchers faced were the aggregation of nanoparticles during the synthesis of the material and its dissolution in the electrolytes during the electrochemical tests. “The interesting idea came up with brain-storming discussion of Dr. Ana Maria Borges Honorato and after multiphases optimizing conditions of synthesis process,” says Khalid. In the material obtained, the carbon layers protect the catalyst nanoparticles and influence the material’s catalytic performance, which is affected by the thickness of these layers and by small variations in their composition. “This nanostructure allowed us to solve not only the problem of particle aggregation during synthesis and the problem of metal segregation/dissolution in electrolytes during the operation, but also to improve the catalytic performance in oxygen reduction, oxygen evolution, hydrogen evolution, ethanol oxidation reactions and general water division, with very competitive values in relation to reference catalysts,” summarizes the postdoctoral fellow.

The work received funding from Brazilian agencies CAPES, CNPq and FAPESP (São Paulo).

Main authors of the paper:  Mohmmad Khalid, Ana Maria Borges Honorato and Hamilton Varela.
Main authors of the paper: Mohmmad Khalid, Ana Maria Borges Honorato and Hamilton Varela.

[Paper: Trifunctional catalytic activities of trimetallic FeCoNi alloy nanoparticles embedded in a carbon shell for efficient overall water splitting. Mohd. Khalid, Ana M. B. Honorato,  Germano Tremiliosi Filho and  Hamilton Varela. J. Mater. Chem. A, 2020,8, 9021-9031.]

Featured paper: Nanorods to develop new anti-inflammatory drugs.

[Paper: Characterization of the structural, optical, photocatalytic and in vitro and in vivo anti-inflammatory properties of Mn2+ doped Zn2GeO4 nanorods. Suzuki, V. Y.; Amorin, L. H. C; Lima, N. M; Machado, E. G; Carvalho, P. E.; Castro, S. B. R.; Souza Alves, C. C.; Carli, A. P.; Li, Maximo Siu; Longo, Elson; Felipe La Porta. J. Mater. Chem. C, 2019, 7, 8216. DOI: 10.1039/c9tc01189g]

nanobastoesA team of researchers from Brazilian universities found, in cylindrical nanostructures known as nanorods, an anti-inflammatory effect equivalent to that achieved by commercial drugs. Researchers have also demonstrated the effectiveness of these nanorods as catalysts (accelerators) in the degradation of a pollutant. These applications are even more relevant considering that the scientific team was able to produce large quantities of the material through a simple and fast process. The work carried out shows the potential of these nanorods for the development of new medicines and for the treatment of effluents.

The work originated about three years ago when Professor Felipe de Almeida La Porta, who had recently joined the faculty of the Federal Technological University of Paraná (UTFPR), Londrina campus, was implementing a research group on nanotechnology and computational chemistry at this university. “Our laboratory was investigating some classes of emerging materials, with the perspective of aligning theory and practice, thus driving new discoveries and applications,” says La Porta. One of the materials studied by the group was zinc germanate (Zn2GeO4), a versatile semiconductor with well-known applications in sensors, catalysts, batteries and other devices.

Together with undergraduate researcher Victor Yuudi Suzuki, the professor started a project in which he synthesized pure Zn2GeO4 nanorods at the UTFPR laboratory with very small percentages of manganese ions. To produce this series of nanorods, they used “microwave assisted hydrothermal synthesis.” The method consists, in broad lines, of mixing aqueous solutions containing certain compounds, heating the final solution in a microwave oven and allowing the compounds to react for a certain period of time at controlled pressure and temperature. In this study, the manganese ion-doped Zn2GeO4 was prepared, and the reactions were performed at 140 °C for 10 minutes. The resulting material from these reactions was collected at room temperature, then washed and dried, which generate the nanorods.

Professor La Porta and his research group were able to optimize one of the process steps, the crystallization of materials, thus reducing the synthesis time from hours to a few minutes, but maintaining the quality of the material and the possibility to control its shape.

After preparing the samples, they traveled from Londrina (state of Paraná) to São Carlos (São Paulo state) to characterize the materials at the Center for Functional Materials Development (CDMF) at the Federal University of São Carlos (UFSCar) and at the Institute of Physics at the University of São Paulo (USP). Together with the local researchers, they were able to analyze the shape, structure and luminescence of the four types of nanorod compositions produced: manganese-free and with 1, 2 and 4% of this element incorporated into the structure of Zn2GeO4.

Finally, knowing that compounds containing zinc, germanium or manganese exhibit considerable effects on living things, the team contacted some collaborators to investigate these properties in the nanorods. Thus, several experiments were performed at the Departments of Chemistry and Pharmacy of the Federal University of Juiz de Fora and at the Federal University of Vales do Jequitinhonha and Mucuri, both in the state of Minas Gerais.

The authors of the paper. From the left: Victor Suzuki, Luís Amorin, Felipe La Porta, Maximo Si Li, Elson Longo, Sandra de Castro, Paloma de Carvalho, Alessandra Carli, Emanuelle Machado, Caio Alvez, Nerilson Lima.
The authors of the paper. From the left: Victor Suzuki, Luís Amorin, Felipe La Porta, Maximo Si Li, Elson Longo, Sandra de Castro, Paloma de Carvalho, Alessandra Carli, Emanuelle Machado, Caio Alvez, Nerilson Lima.

To study the anti-inflammatory action, the team performed in vitro tests (in contact with cells in laboratory containers) and also in vivo tests (using rats with paw edema, within the norms of the Brazilian code for laboratory animal use). Both types of experiments revealed that nanorods with about 4% manganese were the most effective in controlling inflammation. The in vitro tests showed these nanostructures were able to modulate molecules that regulate inflammation without causing cell death (without cytotoxicity). In the in vivo experiments, the nanorods reduced the induced rat paw edema with results similar to that of the application of dexamethasone, a well-known drug of the corticoid group.

“At first, we thought that combining these elements to form a ternary oxide could somehow potentiate these effects. But we had no idea the results would be so significant. Given that the drugs currently available in therapy are proving to be less effective every day, these results may encourage the use of these nanorods, for example in the production of a new pharmaceutical formulation, especially for cases of inflammation,” says Felipe La Porta, who is the corresponding author of the paper that was recently published by the research team in the Journal of Materials Chemistry C (impact factor 6,641).

In addition to proving the potential of the material for this application in the health area, the authors of the paper have experimentally verified the ability of nanorods to degrade a chemical dye widely found in industrial effluents, known as methylene blue. For this application, 2% manganese nanostructures were the most efficient, completely decomposing the dye in 10 minutes. “Due to the manufacture simplicity of this system, coupled with its excellent properties, this material is also promising for cleaning various environmental pollutants, and can be easily recovered at the end of this process,” adds Prof La Porta.

In the center, a cluster of 4% manganese zinc germanate nanorods. Clockwise: photoluminescence measurements of the samples; representation of the structure of manganese-doped zinc germanate; pollutant degradation mechanism and methylene blue degradation measures; anti-inflammatory action of nanorods and other treatments in induced-edema rat paw.
In the center, a cluster of 4% manganese zinc germanate nanorods. Clockwise: photoluminescence measurements of the samples; representation of the structure of manganese-doped zinc germanate; pollutant degradation mechanism and methylene blue degradation measures; anti-inflammatory action of nanorods and other treatments in induced-edema rat paw.

The superior properties that the Brazilian scientific team found in the nanorods with manganese can be related to the structural defects observed in these samples. In fact, the three-dimensional network of atoms that forms zinc germanate is crystalline, that is, organized in regular patterns. The introduction of manganese generates irregularities, and new properties emerge.

The scientific paper that reports this work was selected to be part of the Materials and Nano Research in Brazil collection, prepared by the Royal Society of Chemistry in celebration of the 18th B-MRS Meeting, and can therefore be accessed free of charge until October 15 of this year, here.

The work was carried out with funding from Brazilian research support agencies: the federal CNPq and Capes, and the state Araucaria Foundation, Fapesp and Fapemig.

B-MRS Newsletter. Year 6, issue 2.


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Newsletter of the
Brazilian Materials
Research Society

Year 6, issue 2. March 7, 2019.

Featured Paper

A team of Brazilian researchers has developed a simple, clean and very efficient method to produce hydrogen. These scientists used thin films of graphene and metal nanoparticles as catalysts for a spontaneous chemical reaction that occurs between borohydride and water. The work was reported in the Journal of Materials Chemistry A. Know more.


Featured Scientist

We interviewed Juliana Davoglio Estradioto. This 18-year-old girl holds a collection of national and international awards received for research work carried out during high school, in which she developed biodegradable materials from agro-industrial waste and created applications for them. See our interview.

juliana news

News from B-MRS Members

– Professor Sidney J. L. Ribeiro (IQ-UNESP – Campus de Araraquara), member of B-MRS, was appointed associate editor of the journal Frontiers in Chemistry – Inorganic Chemistry. Know more.

B-MRS News

– The University Chapters Program commemorates the establishment of its 9th unit, formed by a group of 15 students from different areas of the Brazilian Federal University of Pernambuco. Know more.

banner evento

XVIII B-MRS Meeting (Balneário Camboriú, SC, Brazil, September 22 – 26, 2019)

Website: www.sbpmat.org.br/18encontro/

See invitation to abstract subsmission, here.

Abstract submission. The submission of abstracts is open until April 15. Approval, modification, or rejection notifications will be sent by May 31. Final notices for abstracts needing modification will be sent by June 21. See instructions for authors, here.

Symposia. 23 symposia proposed by the international scientific community compose this edition of the event. See the symposia list, here.

Student awards. To participate in the Bernhard Gross Award, authors must submit an extended abstract by July 11 in addition to the conventional abstract. Learn more, here.

Registrations. Registration is now open. More information, here.

Venue. The meeting will be held in the delightful Balneário Camboriú (State of Santa Catarina, Brazil), at the Hotel Sibara Flat & Conventions, located in the center of the city, close to many hotels, restaurants and shops, and only 100 meters from the sea. More information, here.

Memorial lecture. The traditional Memorial Lecture Joaquim da Costa Ribeiro will be given by Professor Yvonne Primerano Mascarenhas (IFSC – USP).

Plenary lectures. Leading scientists from institutions in Germany, Italy, Spain and the United States will deliver plenary talks on cutting-edge issues at the event. There will also be a plenary session by the Brazilian scientist Antônio José Roque da Silva, director of CNPEM and the Sirius project (new Synchrotron Light Lab). Learn more about the plenary sessions, here.

Organization. The chair of the event is Professor Ivan Helmuth Bechtold (Physics Department of UFSC) and the co-chair is Professor Hugo Gallardo (Department of Chemistry of UFSC). The program committee is formed by professors Iêda dos Santos (UFPB), José Antônio Eiras (UFSCar), Marta Rosso Dotto (UFSC) and Mônica Cotta (Unicamp). Get to know all the organizers, here.

Exhibitors and sponsors. 29 companies have already confirmed their participation in the event. Those interested in sponsoring/support can contact Alexandre at the e-mail comercial@sbpmat.org.br.

Reading Tips

– By encapsulating graphene in boron nitride, scientists are able to print patterns with nanolithography, opening up possibilities to use the material in nanoelectronics (paper from Nature Nanotechnology). Know more.

– Scientists improve activity of aluminum nanocatalysts by coating them with MOFs using a strategy inspired by the natural process of wood petrification (paper by Science Advances). Know more.

– Quantum materials: Scientists confirm experimentally that topological material of atomic thickness conducts electricity at the edges, opening possibility of its use in quantum computers (paper of Science Advances). Know more.


– WIN Rising Star Award in Nanoscience and Nanotechnology nominations. Know more.

– Doctoral fellowship in ultra-sensitive bioelectronic transducers in Portugal. Know more.

– Invitation to organize the official International Sol-Gel Society Conference in 2021. Know more.


International Workshop on Advanced Magnetic Oxides (IWAMO 2019). Aveiro (Portugal). April 15 – 17, 2019. Site.

2019 E-MRS Spring Meeting e IUMRS – ICAM. Nice (France). May 27 – 31, 2019. Site.

20th International Symposium on Intercalation Compounds (ISIC). Campinas, SP (Brazil). June 2 – 6, 2019. Site.

10th International Conference on Materials for Advanced Technologies (ICMAT 2019). Singapore. June 23 – 28, 2019. Site.

20th International Sol-Gel Conference. Saint Petersburg (Russia). August 25 – 30, 2019. Site.

YUCOMAT 2019 & WRTCS 2019. Herceg Novi (Montenegro). September 2 – 6, 2019. Site.

XVIII B-MRS Meeting. Balneário Camboriú, SC (Brazil). September 22 – 26, 2019. Site.

19th Brazilian Workshop on Semiconductor Physics. Fortaleza, CE (Brazil). November 18 – 22, 2019. Site.

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You can suggest news, opportunities, events or reading tips in the materials field to be covered by B-MRS Newsletter. Write to comunicacao@sbpmat.org.br.



Featured paper: Graphene and nickel films, the best catalysts for hydrogen production.

[Paper: Nanocatalysts for hydrogen production from borohydride hydrolysis: graphene-derived thin films with Ag- and Ni-based nanoparticles. Leandro Hostert, Eduardo G. C. Neiva, Aldo J. G. Zarbin, Elisa S. Orth. J. Mater. Chem. A, 2018,6, 22226-22233. DOI 10.1039/C8TA05834B]

Graphene and nickel films, the best catalysts for hydrogen production

Thousands of vehicles powered by hydrogen gas already circulate in some regions of the world releasing only water through the exhaust pipes. As a fuel or source of energy, hydrogen is in fact an extremely clean (does not generate harmful emissions) and efficient option (it can produce more energy than any other fuel). However, pure hydrogen does not exist in nature on Earth. It needs to be produced, and most of the hydrogen-generating methods known to date have both economic and ecological drawbacks.

An alternative to these methods was recently presented by a team of researchers from the graduate program in Chemistry of the Brazilian Federal University of Paraná (UFPR). These scientists have proposed a clean, efficient, simple and inexpensive method to produce hydrogen. The team developed new catalysts (compounds that modify the speed of a chemical reaction without being consumed during the reaction), made of graphene and metal nanoparticles, which made hydrogen production feasible through the hydrolysis of borohydride – a chemical reaction still little used in hydrogen generation, notwithstanding its enormous potential as it is clean and very simple.

Photographs and representative schematics of H2 generation by hydrolysis of borohydride catalyzed with graphene and metallic nanoparticles thin films. The films, about 500 nm thick, cover the two sides of a glass plate, covering 15 cm2, which is immersed in a solution of sodium borohydride and water. The photos depict the bubbles of hydrogen gas generated on the surface of the catalyst.
Photographs and representative schematics of H2 generation by hydrolysis of borohydride catalyzed with graphene and metallic nanoparticles thin films. The films, about 500 nm thick, cover the two sides of a glass plate, covering 15 cm2, which is immersed in a solution of sodium borohydride and water. The photos depict the bubbles of hydrogen gas generated on the surface of the catalyst.

In this reaction, which is performed at room temperature, sodium borohydride (NaBH4) molecules, spontaneously react with water molecules generating hydrogen (H2) molecules. The process takes place in only one step, and is performed with catalyst materials, which accelerate the reaction rate.

“The main contribution of this work is the possibility of H2 generation through thin films of graphene nanocomposites,” says Professor Elisa Souza Orth, corresponding author of an article on the work, recently published in the Journal of Materials Chemistry A (impact factor = 9,931). “Nanocomposites of carbon-based materials and metallic nanoparticles have shown many promising applications and we have shown that for the less exploited borohydride hydrolysis they could also be used efficiently,” she adds.

Among the thin film catalysts produced by the UFPR team, the ones that presented better performance were those of reduced graphene oxide with nickel nanoparticles (rGO/Ni). In fact, this nanocomposite, produced with a relatively inexpensive metal, performed better than most of the catalysts previously reported in the scientific literature, including those prepared with noble metals, which cost much more.

In general, this means that small amounts of rGO/Ni (some tens of mg) generated large volumes of hydrogen (400 ml) in a short time (5 hours).

In addition, the films developed by the Brazilian team presented another important characteristic for a catalyst: they can be easily removed from the reaction vessel, washed and dried without damage, thus allowing their reuse. “In this work, we were able to reuse the same nanocatalyst in 10 consecutive cycles, without losing activity,” says Professor Orth.

The doctoral student Leandro Hostert in the laboratory of the postgraduate program of chemistry of UFPR.
The doctoral student Leandro Hostert in a laboratory of the postgraduate program in chemistry of UFPR.

These results were made possible by combining competencies in the production of carbon nanomaterials from the Materials Chemistry Group, coordinated by Professor Aldo José Gorgatti Zarbin, with expertise in catalysis processes of the Catalysis and Kinetics Group, led by Professor Orth. These two UFPR groups have a history of collaboration in the application of carbon materials; initially, in the study of pesticides and, currently, in the development of multifunctional materials with extraordinary catalytic activity.

In addition to the development of catalysts and their application in hydrogen production, the work published in the Journal of Materials Chemistry A included an analysis of the various ways of measuring the catalytic activity of a material. The authors were able to standardize criteria and compare several results obtained in the laboratory and found in the scientific literature. “We have developed a kinetic study that complements the discussion of these complex reactions and can help guide us to a more concise understanding of catalytic activity,” explains Elisa Orth.

The research was carried out under the doctoral program in progress of Leandro Hostert, guided by Professor Orth, and was funded by Brazilian agencies CNPq, CAPES, Araucária Foundation, INCT Nanocarbono, as well as L’Oréal-UNESCO-ABC through the Award for Women in Science (2015 ) and International Rising Talents (2016) received by Elisa Orth.

Featured paper: Aluminum flakes to produce carbon nanotubes.

[Paper: High-yield synthesis of bundles of double- and triple-walled carbono nanotubes on aluminum flakesThiago H.R. da Cunha, Sergio de Oliveira, Icaro L. Martins, Viviany Geraldo, Douglas Miquita, Sergio L.M. Ramos, Rodrigo G. Lacerda, Luiz O. Ladeira, Andre S. Ferlauto. Carbon 133(2018) 53-61.]

Aluminum flakes to produce carbon nanotubes

Scanning electron microscopy image of carbon nanotube bundles obtained by the method of the CTNano team.
Scanning electron microscopy image of carbon nanotube bundles obtained by the method of the CTNano team.

A team of scientists from institutions in Minas Gerais made a promising contribution to the production of carbon nanotubes. These hollow cylinders, whose carbon walls are only 1 atom thick, are already part of some products (batteries, automotive materials, water filters), but their industrial production is still incipient and needs solutions to lower costs and to increase efficiency, among other challenges.

The Brazilian researchers introduced a novelty in a stage of one of the most consolidated techniques for the mass production of nanotubes, chemical vapor deposition (CVD). As a result, the team was able to produce double- and triple-walled nanotube bundles (somewhat similar to two or three hollow cylinders, one inside the other). Thin, long and of high purity, the nanotubes had diameters of 3 to 8 nanometers, lengths up to 50 thousand times the diameter (from 150 to 300 micrometers) and 90% of carbon in their composition.

“The main contribution of this work is the presentation of a scalable and cost effective process for the synthesis of carbon nanotube bundles with large surface area (625 m2/g) and aspect ratio (50000:1),” says Thiago Henrique Rodrigues da Cunha, researcher of the Nanomaterials Technology Center (CTNano) of the Brazilian Federal University of Minas Gerais (UFGM) and corresponding author of this paper, which was recently published in the journal Carbon (impact factor 2017 = 7,082).

The method, in addition to generating good quality nanotubes, allows producing relatively large quantities of this material using relatively low amounts of raw materials. “Even using small systems, it is possible to obtain carbon nanotubes at a kilogram/day scale,” says the researcher. As the nanotubes obtained showed a very large ratio between surface area and mass (more than 625 square meters weighing only one gram), the production of nanotubes by this method could reach a few million square meters per day.

With the nanotubes obtained and a type of alcohol, the scientific team prepared a paste which was distributed over filter paper, forming a film that was separated from the paper when the paste dried. The black film was 40 micrometers thick and was flexible and foldable. Macroscopic aggregates of carbon nanotubes like this are commonly called buckypapers.

On the left, carbon nanotube film (buckypaper) produced by the team. On the right, an airplane made with this buckypaper.
On the left, carbon nanotube film (buckypaper) produced by the team. On the right, an airplane made with this buckypaper.

“The buckypaper produced from these nanotubes exhibited great surface area and good electrical conductivity, which makes them particularly interesting in the manufacture of electrodes for batteries and supercapacitors,” says Thiago da Cunha, who adds that the CTNano team is already working to use the buckypapers in these energy storage devices. A patent on the process was deposited at the end of 2017. “Our intention is to introduce this technology to potential partners in order to convert it into a high value-added product,” reveals Cunha.

The secret of the process

Scanning electron microscopy image of carbon nanotube bundles that grew from both sides of an aluminum flake.
Scanning electron microscopy image of carbon nanotube bundles that grew from both sides of an aluminum flake.

The CVD nanotube production processes take place inside a tube furnace into which gas containing carbon and catalytic nanoparticles are inserted. Subjected to high temperatures, the gas decomposes, and the carbon atoms deposit on top and around the nanoparticles, forming tubes (the nanotubes). The nanoparticles can be prepared in the same furnace used for nanotube growth.

The secret of the method developed by the Minas Gerais team lies precisely in the preparation of the catalytic nanoparticles. In broad lines, it is a matter of preparing a powder containing iron (Fe) and cobalt (Co) on aluminum flakes (material that had never before been mentioned in the scientific literature as a support for the growth of nanoparticles). The mixture is then subjected to temperatures of 350 to 650 °C for 4 hours, in an atmosphere similar to the air we breathe. This process, known as calcination, produces nanoparticles of iron and/or cobalt oxides. Then, the catalyst nanoparticles, still on the aluminum flakes, are introduced into the CVD furnace, whose internal temperature is brought to 730 °C. The ethylene gas (C2H4) is then introduced, which supplies the carbon so that the nanotubes grow perpendicular to the aluminum flakes.

Scientists observed an interesting advantage of using this new medium. During the calcination, a thin layer of aluminum oxide is formed on the surface of the aluminum that encapsulates the nanoparticles and prevents them from agglomerating or spreading. In addition, in the next step of the process, the aluminum oxide acts as a matrix of the nanotubes, driving their growth in the form of aligned bundles.

To test whether the calcination temperature of the nanoparticles would influence their performance as catalysts, the CTNano team carried out some experiments. The conclusion was that calcination at temperatures of 500-550 °C produces more mixed oxide nanoparticles (containing both iron and cobalt, of the CoFe2O4 formula) and produces better results in the production of nanotubes, both quantitatively (yield) and qualitative (diameter of the nanotubes).

“Unlike other methods described in the literature, which generally display low yield and are dependent on relatively expensive techniques (evaporation, sputtering) for the preparation of the catalyst, we describe in this paper a simple method to produce a catalyst in powder form, which can be used for continuous production of few-walled nanotubes using the chemical vapor deposition technique (CVD),” summarizes Thiago da Cunha.


The work was funded by the Brazilian agencies Fapemig (Minas Gerais State Research Foundation) and CNPq, as well as Petrobras. The work was carried out at CTNano, except for the microscopy images, conducted at the UFMG Microscopy Center.

CTNano emerged in 2010 based on the motivation to develop products, processes and services using carbon nanotubes and graphene, in order to meet industrial demands in line with the training of qualified human resources. The research realized in CTNano has already originated 26 patents and contributed to the development of more than 200 researchers in the area. According to Thiago da Cunha, CTNano will inaugurate, in 2018, its own headquarters with an area of approximately 3,000 m², located in the Technology Park of Belo Horizonte (BH-TEC).

Authors of the paper, from UFMG, except for Viviany Geraldo, who is a professor at the Federal University of Itajubá (UNIFEI).
Authors of the paper, from UFMG, except for Viviany Geraldo, who is a professor at the Federal University of Itajubá (UNIFEI).


Brief interviews with scientists: Joan Ramón Morante Lleonart (Institut de Recerca en Energia de Catalunya, Spain).

Prof. Joan Ramón Morante Lleonart
Prof. Joan Ramón Morante Lleonart

Villain of global warming and ocean acidification, the excess of carbon dioxide generated by human activities can be used to produce very useful compounds.

One example is the production of fuels from carbon dioxide, water and sunlight through photosynthesis-like processes, in which catalytic materials can play a key role in significantly increasing the efficiency of reactions.

Scientists from several countries are currently addressing a number of scientific and technological challenges related to the “recycling” of carbon dioxide. Their ultimate objective is to enable the so-called circular carbon economy, a system based on the use of carbon dioxide, renewable energy and environmentally friendly materials, and on the principle of minimizing waste and maximizing reuse.

One of these scientists is Joan Ramón Morante Lleonart, director of the Institute of Energy Research of Catalonia (IREC) and Professor of the Faculty of Physics of the University of Barcelona. Morante, who holds a PhD in Physics from the University of Barcelona, is also the editor-in-chief of the Journal of Physics D: Applied Physics (IOP Publishing). According to Google Scholar, his scientific production has more than 24,000 citations and his h-index is 82.

This Spanish scientist will be in September at the XVII B-MRS Meeting, where he will offer a plenary lecture entitled “Catalyst materials for solar refineries, synthetic fuels and procedures for a circular economy of the CO2”.

See our brief interview with Professor Morante.

B-MRS Newsletter: – Which materials can play an important role in circular economy of the CO2?

The circular CO2 economy implies different materials. First, the CO2 itself that must be captured and purified. These processes are not direct and even require the improvement of these steps, especially the development of materials for membranes that help to properly separate the CO2 from other components that, although smaller, such as sulfur can degrade the catalytic materials.

This is necessary both for the capture of CO2 from the carbon consumption of fossil origin and for the CO2 contained in the processes of fermentation and putrefaction that produce biogas.

However, apart from the caking process, the most critical point that requires the contribution of a deep knowledge of the materials is the step of the catalytic transformation of CO2 to achieve its direct reduction to products such as CO, methanol, formic acid, etc. . or its transformation, using other feed-stock, to methane (synthetic methane) or other products for example by hydrogenation of CO2 (methanation according to the reaction named reaction of Paul Sabatier).

These processes require not only the development of efficient catalysts but also materials for new reactors that combine their resistance to use, being able to resist corrosive conditions together with their thermal dissipation capacity in some cases, or electrical conductivity in other cases, or the lighting conditions for those cases in which the solution passes through the direct transformation of CO2 using the photons of the sun.

The development of these materials offers a magnificent opportunity to apply nanomaterials, being necessary to have large active surfaces per gram of material and controlled characteristics at the nanometer level avoiding degradation phenomena.

All these features constitute a great opportunity for developing science and technology promoting, at the same time, the transfer of science toward larger knowledge as well as new business opportunities giving answers to a truly problem of our society as it is the consumption of fossil energy sources that generate climatic change.

B-MRS Newsletter: – We want to know your work a little more. Choose your favorite scientific contribution and describe it briefly, in addition to sharing the reference.

Some years ago I was working on the compatibility of different materials with the microelectronics processes just looking for the integration of different functionalities (sensors and actuators) together with the processing units. In a way, it is a biomimetic activity because the scientific community tries to do something similar to living beings, that is, put the senses (sensors) to have a signal as information and connect it to a brain (processors) to process it.

In these activities it was necessary to generate electrical signals and control them. From this, I moved to generate electrical signals in different environments but now considered not as a signal of information but as a source of energy.

Again, the best features are achieved by controlling these phenomena on a nanometric scale and that is why now my activities are focused on “nano energy” in order to produce GWh.

Currently, I am focused in the mechanisms of energy transfer in solid interfaces involving electrons, photons and phonons as well as chemicals.

Likewise, I am specialized in the development of renewable energy devices and systems for applications in the field of energy and environment based on nano structures and their functionalization. So I have paid my attention on advanced materials and structures for artificial photosynthesis including the production of hydrogen and fuels at solar refineries. One of my main objectives is how to storage the electrical energy beyond the hydraulic pumping or the limited capacity by using batteries. Chemical storage using hydrogen or synthetic methane or biomethane constitute my main goal although I am also working on electrochemical batteries.

So if I check my last published papers, from one hand, I could highlight “Recent developments in organic redox flow batteries: A critical review” published in J. of Power Sources which is going beyond the lithium ion approaches for batteries , but from the other hand, I would like to underline “Enhanced photoelectrochemical water splitting of hematite multilayer nanowire photoanodes by tuning the surface state via bottom-up interfacial engineering” or “A prototype reactor for highly selective solar-driven CO2 reduction to synthesis gas using nanosized earth-abundant catalysts and silicon photovoltaics” both published in Energy and Environmental Science. Especially the last one is very representative of the above discussed issues.

B-MRS Newsletter: – Choose also a technological contribution that you have participated in: a case of transfer to the industry or a patent, for example, and make a brief description.

Our institute promotes and encourages the transfer of technology and the generation of patents only linked to its industrial exploitation.

During these last years we have patented some aspects of the technology to produce industrial solar or synthetic fuels. So with one of our industrial collaborators some patents have been carried out as “filter-press photoelectrochemical water oxidation and CO2 reduction cell” or “substrate-electrode interface illuminated photoelectrodes and their photoelectrolechemical cells”.

However I would like to indicate another of the patents made in collaboration with other groups that open a new perspective to the catalytic materials for the catalytic conversion of CO2. Its title is “procedure for the reduction of carbon dioxide to methane by catalytic activated by DBD plasma” and deals with the development of new concepts of catalytic materials that are subjected to the action of a plasma which changes all the conditions of the chemical reactions that take place on the surface of the catalyst at the same time that the own plasma contributes a complementary energy to have a different catalytic behavior. This allows to develop other behaviors and concepts. Thus, it has been achieved under adiabatic conditions to have a conversion rate of CO2 at room temperature comparable to that of a standard isothermal thermochemical conversion process at 300-400 °C. This opens new routes to implement more economical and high performance reactors.


For more information on this speaker and the plenary talk he will deliver at the XVII B-MRS Meeting, click on the speaker’s photo and the title of the speech here https://www.sbpmat.org.br/17encontro/home/

Featured paper. Super efficient nanoparticles to catalyze production of hydrogen, an alternative fuel.

[Paper: Hybrid tantalum oxide nanoparticles from the hydrolysis of imidazolium tantalate ionic liquids: efficient catalysts for hydrogen generation from ethanol/water solutions. Virgínia S. Souza, Jackson D. Scholten, Daniel E. Weibel, Dario Eberhardt, Daniel L. Baptista, Sérgio R. Teixeira and Jairton Dupont. J. Mater. Chem. A, 2016, 4, 7469-7475. DOI: 10.1039/C6TA02114J.]

Super efficient nanoparticles to catalyze production of hydrogen, an alternative fuel.

While some automobiles which use hydrogen fuel are entering the market, scientists from around the world are still trying to find cleaner, more sustainable, safer and cost-effective ways to generate and store hydrogen. In fact, even though it is the most abundant element in the universe and found in the water and in numerous other compounds, hydrogen cannot actually be found in its pure form on our planet. It must therefore be obtained from other chemical compounds.

One of the best methods to produce hydrogen, from ecological and economical points of view, is water splitting. This technique consists of separating water molecules into its two primary elements, generating hydrogen (H2) and oxygen (O2) gases. This separation can be achieved through the use of the abundant solar energy, at room temperature. However, in practice, for sunlight to split one water molecule, it requires nanoparticles made of semiconducting materials to act as catalysts, or more specifically, as photocatalysts.

In a study fully carried out in Brazil, a team of scientists developed a new simple and efficient method to produce tantalum oxide nanoparticles (Ta2O5) with outstanding performance catalysts for hydrogen generation. The research was reported in a paper recently published in the Journal of Materials Chemistry A (impact factor: 8.262).

Fotos dos autores principais do artigo. Começando pela esquerda do leitor: a doutora Virgínia Souza, o professor Jackson Scholten e o professor Jairton Dupont.
Picture of the main authors of the paper. From left to right: PhD Virgínia Souza, Prof. Jackson Scholten and Prof. Jairton Dupont.

This study was funded by the Brazilian research agencies CAPES and CNPq, as the doctoral research of Virgínia Serra Souza at the Chemistry Institute of the Federal University of Rio Grande do Sul (IQ-UFRGS), under the guidance of Professor Jairton Dupont.

“The idea for this research came when we were looking for an alternative and efficient route for the synthesis of Ta2O5 nanoparticles, and after some experiments we decided to test the possibility of using ionic liquids as stabilizing sources and agents of the nanomaterials”, says Professor Jackson Damiani Scholten, who is one of the corresponding authors of the paper and member of the research group of IQ-UFRGS. This group has extensive experience in the study and development of ionic liquids (salts which are in liquid state at room temperature). Due to their physicochemical properties, ionic liquids can be used in the preparation of nanoparticles as stabilizers to keep the particles in the nanometric range.

Souza, Scholten and Dupont prepared two types of ionic liquids containing tantalum and create the conditions for the hydrolysis reaction (breaking the chemical bonds of a compound by the addition of water). The elements resulting from the hydrolysis, from the water and the ionic liquid, recombine to form tantalum oxide nanoparticles.

The team realized it had produced tantalum oxide nanoparticles ranging between 1.5 and 22 nm, the smaller ones had been generated from one of the ionic liquids and the larger ones from the other. With the assistance of Professor Daniel E. Weibel, also from IQ-UFRGS, they studied the surface composition of the nanoparticles. These scientists proposed that the nanoparticles obtained were hybrid: remains of ionic liquid were observed around the tantalum oxide.

To see how the nanoparticles behaved as catalysts in the separation of water molecules to generate hydrogen, the team conducted photocatalytic tests at the facilities of the Institute of Physics – UFRGS, provided by Professor Sérgio R. Teixeira. The tests were carried out in a solution that besides water contained ethanol – a compound that helps to increase the hydrogen production rate.

“We were delighted that the Ta2O5 nanoparticles showed one of the best results ever published for the production of H2 from a water/ethanol solution”, recalls Professor Scholten. In the article, this exceptional result was attributed to the presence of ionic liquid in the nanoparticles. “We believe that the residual ionic liquid enhances the formation of a hydrophilic regions on the surface of Ta2O5, favoring the approximation of polar molecules (water and ethanol)”, explains Scholten. To be certain about this, the scientists removed the ionic liquid from the nanoparticles by heat treatment and confirmed their very low photocatalytic activity.

In another stage of the research, Dario Eberhardt, then professor at the University of Caxias do Sul (UCS), collaborated with the team in the deposition of roughly 1 nm platinum nanoparticles on the surface of the hybrid tantalum oxide nanoparticles by the sputtering technique, carried out at IF-UFRGS. Professor Daniel L. Baptista, of IF-UFRGS, helped to characterize the material. In the tests, the performance of the tantalum oxide nanoparticles with photocatalytic ionic liquid was even better with the addition of platinum.

This work, carried out in southern Brazil, presented a new method to produce super-efficient catalysts for hydrogen production, a promising alternative fuel from water and ethanol, two renewable and abundant resources.

This image provided by the authors of the paper exhibits the process to produce tantalum oxide nanoparticles from the hydrolysis of ionic liquids, followed by the deposition of platinum nanoparticles on the first material, and the application of the second material to obtain hydrogen gas in the “water splitting” process.
This image provided by the authors of the paper exhibits the process to produce tantalum oxide nanoparticles from the hydrolysis of ionic liquids, followed by the deposition of platinum nanoparticles on the first material, and the application of the second material to obtain hydrogen gas in the “water splitting” process.