Tag: 1º Simpósio Nacional de Física do Estado Sólido e Ciência dos Materiais

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

Posted on Wednesday 30 de May de 2018
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: Rubber under Pressure for Solid-State Cooling.

Posted on Tuesday 30 de January de 2018

[Paper: Giant Barocaloric Effects in Natural Rubber: A Relevant Step toward Solid-State Cooling. N. M. Bom, W. Imamura, E. O. Usuda, L. S. Paixão, and A. M. G. Carvalho. ACS Macro Lett. 2018, 7, 31-36. dx.doi.org/10.1021/acsmacrolett.7b00744]

Rubber under Pressure for Solid-State Cooling

A team of researchers from Brazil has found that vulcanized natural rubber prevails over any other material already studied in its capacity to change temperature by being compressed and decompressed – a phenomenon known as “barocaloric effect.”

The discovery opens up interesting possibilities of using vulcanized natural rubber in advanced applications, especially in the area of “solid-state cooling.” This term refers to refrigeration systems (such as refrigerators or air conditioners) that are based on the use of solid state refrigerant materials to absorb the heat of the system to be cooled and transferred to an external environment. Conventional devices use fluids (gaseous and liquid states). The research was reported in an article recently published in ACS Macro Letters, a journal of the American Chemical Society publisher in the field of Polymer Science and the related matters, whose impact factor is 6,185.

“Since natural rubber heats up when pressed (more than 20 degrees above the initial temperature) and cools when the pressure is released (at least 20 degrees below the initial temperature), we believe it can be used as refrigerant material in a refrigerator,” explains Alexandre Magnus Gomes Carvalho, researcher at the Brazilian Synchrotron Light Laboratory (LNLS) and corresponding author of the article.

Schematic representation of the barocaloric cycle, based on confined compression and decompression processes.
Schematic representation of the barocaloric cycle, based on confined compression and decompression processes.

The representation of the barocaloric cycle of a solid material, shown on the side, gives an idea of how vulcanized natural rubber can cool a system, removing heat from it and releasing it to the external environment. In process 1 of the cycle, the rubber (represented by the yellow rectangles) compresses quickly and consequently its temperature increases abruptly (Thot).  In process 2, pressure on the rubber is kept constant, but its temperature is reduced by releasing heat to the external environment for thermal equilibrium. Interestingly, in nature two bodies or systems with different temperatures tend to seek thermal equilibrium – the state in which both temperatures are equal. This equilibrium is achieved by transferring heat from the system or hotter body to the cooler one. In process 3 of the cycle, when the rubber reaches its initial temperature (Ti), the pressure rapidly drops, causing the rubber temperature to decrease abruptly (Tcold). In process 4, the external environment transfers heat to the rubber, again for thermal equilibrium. When the rubber reaches the initial temperature, the cycle resumes from a new compression process.

To investigate the barocaloric effect of rubber, Carvalho and the other authors of the paper used samples of vulcanized natural rubber of about 1 cm in diameter. They carried out a systematic study changing the pressure exerted on the samples and their initial temperature and measuring the temperature and entropy variations (both directly related to the heat variation of a system). The experiments were carried out at the Laboratory of i-Caloric Materials (LMiC), one of the thematic laboratories of LNLS, at CNPEM, whose coordinator is Alexandre Carvalho.

After obtaining the experimental measurements of the barocaloric properties of vulcanized natural rubber, the researchers compared them with the results, found in the scientific literature, of other materials with giant or large barocaloric effect. In this comparison, vulcanized natural rubber surpassed all its “competitors.”

Foreground: pressure cell and sample of vulcanized natural rubber subjected to several cycles of compression and decompression. Background: chart showing temperature measurements as a function of time for different pressure variations.
Foreground: pressure cell and sample of vulcanized natural rubber subjected to several cycles of compression and decompression. Background: chart showing temperature measurements as a function of time for different pressure variations.

The barocaloric effect of vulcanized natural rubber also has advantages with respect to caloric effects generated from the application of a magnetic or electric field, for example – effects that are also studied for solid refrigeration applications. In fact, while relatively low pressures have generated a giant caloric effect on rubber, to produce significant magnetocaloric and electrocaloric effects, very high fields and much more expensive materials than natural rubber are necessary, explains Carvalho.

Besides reporting for the first time in the scientific literature the giant barocaloric effect of vulcanized natural rubber, the paper in ACS Macro Letters contains another important scientific contribution. “The second major contribution is the fact that, for the first time, the effect of the glassy transition of a polymer on the barocaloric effect has been shown,” states Carvalho. The glass transition is a reversible change that occurs in rubber and other materials at a certain temperature. Above the transition temperature, the polymer chains of the rubber acquire more mobility, making the material “rubbery” (more flexible and less hard). Below that temperature, the mobility of the chains decreases and becomes “vitreous” (rigid and relatively brittle). In the ACS Macro Letters article, the authors proposed that the temperature and entropy changes that derive from the compression and decompression of natural rubber are related to the heat generated by the mobility of the polymer chains. Compression of the rubber would lead to a decrease in mobility, which would explain the much lower temperature changes in the vitreous state than in the rubbery state.

As for the application of the discovery, the cooling mechanism based on the barocaloric effect of solid state materials may seem simple, but transferring it to a real device is not easy.  “The barocaloric effect on different materials has been studied for several years, but there is still no barocaloric refrigerator prototype patented or described in a paper, as far as we know,” says Carvalho. “Despite the difficulties, we are considering developing a prototype together with researchers from the Department of Mechanical Engineering at the Brazilian State University of Maringá (UEM),” he announces.

History of the work

The idea of the work reported in ACS Macro Letters began in mid-2016 at CNPEM, when the researcher Alexandre Carvalho, the postdoc Nicolau Bom and the student Érik Oda Usuda came across a paper on the elasto-caloric effect of natural rubber (the temperature variation induced by stretching the material), published in Applied Physics Letters. The scientific trio then wondered if an equivalent effect would occur if the rubber were compressed rather than stretched. “More specifically, we wanted to know what would happen in a confined compression,” Carvalho details. They performed the first tests with simple equipment: a pressure cell developed by them and a manual hydraulic press to apply different loads. To prepare the sample, the team used an old school eraser turned into a billet to be fitted into the pressure cell. “The results were encouraging, as we observed that the rubber heated and cooled about 10 degrees from ambient temperature under a relatively low pressure range,” says Carvalho. In early 2017, PhD student William Imamura and postdoc Lucas Soares de Oliveira Paixão joined the group and also devoted their efforts to studying the barocaloric effect of vulcanized natural rubber and other polymers. “We improved our experimental apparatus and our methodology, culminating in the results published in ACS Macro Letters, which will be part of Érik Usuda’s master’s dissertation,” relates Carvalho, who coordinates the LMiC as well as the LNLS XRD1 beamline. In this line, which will be transferred to Sirius (the latest generation synchrotron light source under construction at CNPEM), studies of thermomechanical properties of polymers can be carried out simultaneously with synchrotron radiation analyses, announces Carvalho.

The research was carried out with funding from Brazilian agencies Fapesp, CNPq and Capes, and also LNLS and CNPEM funding.

The authors of the paper in the XRD1 beamline. From left, Lucas Soares de Oliveira Paixão (LNLS postdoc), Alexandre Magnus Gomes Carvalho (LNLS researcher), William Imamura (PhD student at Unicamp and LNLS), Érik Oda Usuda (master student at Unifesp and LNLS), and Nicolau Molina Bom (LNLS postdoc).
The authors of the paper in the XRD1 beamline. From left, Lucas Soares de Oliveira Paixão (LNLS postdoc), Alexandre Magnus Gomes Carvalho (LNLS researcher), William Imamura (PhD student at Unicamp and LNLS), Érik Oda Usuda (master student at Unifesp and LNLS), and Nicolau Molina Bom (LNLS postdoc).

20th anniversary of the establishment of the São Carlos Institute of Physics, and six decades participating in the history of Materials research in Brazil.

Posted on Friday 28 de November de 2014

2014 is a celebration year for one of the protagonist institutions of the history of Materials research in Brazil. The São Carlos Institute of Physics (IFSC), from University of São Paulo (USP), celebrates its 20th anniversary.

However, the origins of IFSC and its contributions to Brazilian Materials Science and Engineering date back to 60 years ago. “From its origins, IFSC had a central role in the development of Materials Science and Engineering, since Materials research was present with the pioneers of IFSC,” says Professor Antonio Carlos Hernandes, IFSC dean from 2010 to 2014 and researcher in the field of Materials.

The beginning of the history can be set in 1953, when USP, which had been founded in 1934, opened a teaching and research facility in the then small city of São Carlos, in the heart of the state of São Paulo. It was the School of Engineering of São Carlos (EESC), which exists to the present. At the time, the dean of the school, Theodoreto Souto, mandated to form a team of lecturers and researchers, recruited professors to São Carlos, mainly in São Paulo (USP), in Rio de Janeiro and abroad, but failed for them to settle in town for long.

Sergio Mascarenhas in 2012. Image: SBPMat.

From Rio de Janeiro, the first to integrate the EESC professors’ team was physicist Armando Dias Tavares, assistant of Joaquim da Costa Ribeiro in the Physics laboratories of the National School of Philosophy of the University of Rio de Janeiro (now Federal University of Rio de Janeiro, UFRJ). Then, collaborators and students of Dias Tavares, who had learned to do science in the “school”  of Costa Ribeiro and Bernhard Gross (main pioneers of Materials research in Brazil) left the “marvelous city” to the inland of São Paulo, invited by Souto. Among them, the newly graduated in Physics and Chemistry and honeymooners Sergio Mascarenhas Oliveira and Yvonne Primerano Mascarenhas – a couple who leaved an important legacy in the history of Materials Science and Engineering in the region and in the country – arrived in São Carlos in 1956.

At a time when most of the human and material resources for research in Physics, in the world and in Brazil, were intended for Nuclear and High Energy Physics, the Mascarenhas couple chose to start studies in Condensed Matter Physics, field they had worked with Costa Ribeiro in Rio de Janeiro. Documents prepared by IFSC state that Sergio and Yvonne saw two possibilities in that area for the group of São Carlos: to internationally stand out in a field where there was less competition, and to generate applications that had a positive impact on the region’s economy and quality of life of its population.

Thus, in the 1960s, Sergio Mascarenhas created the Condensed Matter Physics Group. “Thanks to a very strong exchange between USP in Sao Carlos, and the universities of Princeton and Carnegie Mellon in the United States, and also groups from England and Germany, mainly in Stuttgart, we managed to establish a very intense research training program, which continues to this day”, Mascarenhas commented in an interview granted in 2013 to the SBPMat Newsletter. Among the works with the greatest impact conducted at the time by the São Carlos group, it is possible to mention research related to defects in crystals, such as ionic crystals with a color core, which were later used for optical memories.

In the late 1960s, a new teaching and research institution, the Federal University of São Carlos (USFCar), was created in town, with the effective participation of professors of the EESC group. In particular, Sergio Mascarenhas, who was the first dean (pro tempore) of the university, proposed the creation of the first graduate course in Materials Engineering in Latin America, seeking to build a bridge between Materials Science and the generation of products, processes and services. The course started its activities in 1970.

In another pioneering initiative in the Materials field, the São Carlos group, with Sergio Mascarenhas as head of the organization, hosted the Brazilian community of solid state physicists (then consisting of about 50 researchers) in town to conduct the “First National Symposium on Solid State Physics and Materials Science “in a small shed.

Building of the São Carlos Institute of Physics and Chemistry  in 1970. Image: IFSC/USP.

As a result of the growth, institutionalization and gain of autonomy trodden by Mascarenhas and colleagues of the São Carlos group, in 1971 the Institute of Physics and Chemistry of São Carlos (IFQSC) was created, and the first dean was Mascarenhas himself. IFQSC had from its very beginning a Department of Physics and Materials Science, and a Department of Chemistry and Molecular Physics. Another step was taken in 1994 when IFSC was dismembered, giving rise to the Institute of Chemistry of São Carlos (IQSC) and IFSC, whose first dean was Yvonne Primerano Mascarenhas.

Another milestone in the part of IFSC in the history of Materials research in Brazil was the creation, in 1993, of the inter-unit program in Materials Science and Engineering at USP São Carlos. Managed by IFSC, the program brings together professors of this Institute, IQSC and EESC, as well as researchers from other institutions in the region.

Action with academic and social impact

Besides participating in the inter-unit program, IFSC has one of the most acknowledged and applied postgraduate programs in Physics in the country, which has obtained, since its creation, full marks in assessments from the Federal Agency for the Support and Evaluation of Graduate Education (CAPES). Within its master’s and doctorate, it is possible to perform research in a wide range of topics, including several possibilities in the Materials field, from fundamental research in Condensed Matter Physics to studies on semiconductor materials, polymers, ceramics and glass. Also in the Materials field, IFSC currently has consolidated research groups, for example, the Polymer Group of “Professor Bernhard Gross,” and is home to large projects such as National Institutes of Science and Technology (INCTs) and Research, Innovation and Dissemination Centers.

However, the impact of academic performance of the São Carlos group in the Materials field has exceeded the limits of the city of São Carlos. According to Professor Antonio Carlos Hernandes, the first consequence of this performance was the graduation of doctors (PhD) who began to operate in such field in other higher education institutions. “Thus, many university and research centers operating in Materials today have the IFSC training on their DNA”, says Hernandez.

“IFSC brings together what is essential to the quality of Materials research, with equipment and people with experience in various types of materials,” says Professor Osvaldo Novais de Oliveira Junior, deputy dean of IFSC for the period 2012- 2016. Relying on these features, Novais adds, hundreds of masters and doctors graduated in Materials, many of which have become leaders of research groups in all regions of Brazil. “These leaders of various institutions, as well as others who are part of IFSC, currently play an important role in organizing the Materials community in the country, acting in the Brazilian Materials Research Society (SBPMat), coordinating events and national and international cooperation programs, and formulating public policies”, he adds.

But the impact of IFSC’s performance in the Materials field goes beyond the academic environment. Professor Hernandes highlights, among other examples, the creation of technology-based companies located in the city of São Carlos. “These high-tech companies originated from IFSC researchers work, often involving Materials research”, professor Novais states, which also brings up another type of social contribution made by professors and researchers of the institute, the “tireless work of popularization of science, with various programs for students of primary and secondary education, as well as for the general public. “