Lab profile: Yury Gogotsi, Drexel University

Carbon nanomaterials – graphene, nanotubes, nanodiamond and nanoporous carbons – and two-dimensional carbides and nitrides (MXenes) offer a wealth of possibilities for energy, water and biomedical applications.

Yury Gogotsi, a Distinguished University Professor and Charles T. and Ruth M. Bach Professor of Materials Science and Engineering at Drexel University and Director of the A.J. Drexel Nanomaterials Institute, has pioneered research on these materials with the aim of significantly decreasing the time between discovery and commercial application. In recognition of his efforts, Yury is the winner of the 2021 Materials Today Innovation Award  (https://www.materialstoday.com/materials-chemistry/news/2021-materials-today-innovation-award-winner/), which is given to leaders in materials science who have made advances in cutting-edge research that have opened a new, significant fields of research and resulted in impactful, practical applications.

Yury received his M.S. and Ph.D. from Kiev Polytechnic Institute and has a D.Sc. from the Institute of Materials Science, National Academy of Sciences in Ukraine. After time as a research scientist at the University of Karlsruhe in Germany, Tokyo Institute of Technology in Japan, University of Oslo in Norway, and the University of Tubingen in Germany, Yury was appointed as an assistant professor at the University of Illinois at Chicago. He has been at Drexel University since 2000. He has received numerous other awards during his career, including the ACS Award in the Chemistry of Materials, the International Ceramics Prize, and the Energy Storage Materials Award.

As well as his own research, Yury serves on the editorial boards of a variety of journals including Energy Storage Materials, Current Opinion in Solid State and Materials Science and Nano Energy.

Yury talked to Materials Today about his current research and future plans.

How long has your group been running?

I joined Drexel University in September 2000 and started my Nanomaterials Group. Our lab has been growing and expanding since then. In 2003, Drexel University established the A.J. Drexel Nanotechnology Institute (DNI) of which I became its founding director. In 2017, it was renamed the A.J. Drexel Nanomaterials Institute to better reflect the scope of our research and educational activities.

How many staff currently makes up your group?

My group currently includes about 30 people – including staff members, assistant research professors, post-docs, more than a dozen PhD students and several undergraduates, as well as MS and BS students. We also have a varying number of visiting researchers from many countries around the world, who greatly contribute to our research activities.

What are the major themes of research in your group?

MXenes are the key target of our research nowadays. MXenes were discovered in collaboration with my colleague Michel Barsoum about a decade ago, when Ti₃C₂ synthesis was accomplished by our student Michael Naguib using selective etching of Al from Ti₃AlC₂. Their composition is M_n+1XT_x, where M is an early transition metal, X is C and/or N, n = 1-4, and T_x represents surface terminations (e.g., O, OH, F, S). Well over 100 distinct chemical compositions with in-plane or out-of-plane ordering on the M sites have been predicted and already ~30 produced. Adding in known surface terminations takes the number to over a thousand compositions. Together with possible mixed terminations, solid solutions on M and X sites (dozens already reported, including high-entropy 2D structures), the permutations are practically infinite. MXenes, unlike the majority of other 2D materials, do not have bulk analogues when restacked because of their surface terminations.

How and why did you come to work in these areas?

First, there were carbide-derived carbons: an amazing large family of nanomaterials made by selective etching of metals and metalloids (Ti, Zr, Si, B, etc.) from metal carbides. We made porous carbons with a tunable pore size, graphene, nanotubes and other interesting materials, all without a catalyst and in scalable processes. Since 2010, we have been using the selective etching approach to make MXenes using monoatomic or diatomic layers of metals from MAX phase ceramics or other layered precursors. When we discovered MXenes, it became clear from the beginning that this material family was going to grow quickly because of their many possible structures and an almost infinite number of compositions. 2D materials possess physical properties that differentiate them from their 3D counterparts. This richness of chemical and structural diversity, in turn, allows for unprecedented property tunability. Moreover, not just discrete, but continuous tuning of physical properties is possible using solid solutions, as already demonstrated for plasmon resonances and optical properties. The electrical conductivity of a given MXene composition can be readily modified over several orders of magnitude by varying its surface terminations. In a similar manner, the work function changes from <2 eV to >6 eV just by varying the surface terminations from OH to O.

Since their chemistry is distinct from other 2D materials, MXenes offer unusual combinations of properties. Many can be considered as hydrophilic 2D metals that can be dispersed in water and processed from aqueous colloidal solutions or liquid-crystalline suspensions with no additives. This robust metallic conductivity, coupled with scalable synthesis and, for the most part, earth abundant elements such as Ti, has been the key to MXenes' usefulness in a wide range of applications. The latter span from electrode materials and passive components for high-power electrochemical energy storage devices, electromagnetic interference shielding, antennas, to dialysis, water purification and desalination, chemical catalysis and electrocatalysis, gas and pressure sensing, photothermal cancer therapies and theranostics, additives for ceramic, metal and polymer composites, lasers and LEDs, solid lubricants, implantable electrodes, interconnects for circuits and photodetectors, among many others.

What facilities and equipment does your lab have?

A little over two years ago we moved into a new 7400 sq. ft. fully renovated and well-equipped laboratory in the Bossone Research Enterprise building on Drexel Campus. This is probably one of the best equipped labs on campus. Our lab has 13 fume hoods, two glove boxes, and a variety of equipment for synthesis of MAX phases and MXenes (furnaces, custom-made reactors, centrifuges, etc.). We also have equipment for the manufacture and characterization of batteries and supercapacitors (potentiostats, battery cyclers, etc.), as much of our research is in the energy storage field. Of course, we also have equipment for characterization of pore size, surface area, particle size, zeta-potential and other properties of nanomaterials. Thermal analysis, optical microscopy, UV-vis spectroscopy, Fourier Transform Infrared spectroscopy, Raman spectroscopy and many other characterization techniques are also used in my lab. In addition, my students and post-docs have access to electron microscopes, diffractometers and other tools in the Material Characterization Core facility of Drexel University.

Do you have a favorite piece of kit or equipment?

I have a Raman spectrometer in my lab and this technique has been my favorite since my first exposure to it at the Tokyo Institute of Technology during my post-doc with Professor Masahiro Yoshimura in 1992. I have purchased several Raman spectrometers for universities where I worked over the past 30 years. The technique is very powerful, especially for the characterization of carbons, ceramics, semiconductors, 2D and nanomaterials. I have used it to solve many problems related to silicon, carbon nanomaterials (nanotubes, nanodiamond, carbide-derived carbons, graphene, etc.) and we are using it now to characterize MXenes. We have also expanded the technique to surface-enhanced and tip-enhanced Raman spectroscopy of MXenes in the last few years. In situ electrochemical studies are next. I am also looking forward to upgrading our Raman setup to add tip-enhanced Raman spectroscopy and other advanced Raman tools.

What do you think has been your most influential work to date?

If one judges by the number of citations, our article with Patrice Simon on materials for electrochemical capacitors, which was published in Nature Materials in 2008, is the champion, as it has been cited more than 15,000 times. This work really shaped the field of materials for capacitive energy storage. Our research on the effect of pore size on capacitance and ion desolvation in porous carbons has led to a scientific breakthrough in the field and, ultimately, resulted in the development of a new generation of supercapacitors that facilitate the storage and utilization of electrical energy.

While work on energy storage materials continues in my lab, our research on MXenes has gained in momentum over the past five years. Our paper in Advanced Materials reporting the discovery of the first 2D carbide MXene, Ti₃C₂, is picking up citations quickly – increasing from about 1000 citations per year in 2020 to about 1500 in 2021. Our review article on 2D metal carbides and nitrides (MXenes) for energy storage, published in Nature Reviews Materials in 2017, is already the most cited paper in that journal. The field of MXenes has opened tremendous opportunities for new discoveries.

What is the key to running a successful group?

I try to create the most attractive setting in which to study and perform research so that we can develop, recruit, and retain the best and brightest students, scientists, and engineers from within the United States and around the world. My group has always been very diverse, with people from various engineering and science backgrounds and more than 10 countries working together. For success in research, we need to have a strong team of people who are motivated, excited about research, collaborative and share the same values. Staff members are critical to running the lab. Luckily, I have an excellent team.

How do you plan to develop your group in the future?

We are always exploring new research directions. New MXenes and novel methods of synthesizing MXenes and their MAX phase precursors are on my agenda at the moment. Translational research and technology transfer will increase in importance, I believe. I am also getting involved in an increasing number of projects related to the use of MXenes in smart textiles, wearable and epidermal electronic devices, as well as biomedical applications.

We will need to buy and build additional tools for this kind of research in the future. And, of course, lab equipment is operated by people. I expect new students, post-docs and visiting scientists will bring their expertise and work to create new knowledge. We also collaborate with many research groups in the United States and abroad, who have complementing expertise. Many of the problems the world faces, such as fighting dangerous infections, protecting the environment, producing energy from renewable sources, and providing pure drinking water, are common for all. Links across international boundaries will help solve these problems more quickly and thoroughly.

Key publications

1. A. VahidMohammadi, J. Rosen, Y. Gogotsi. The World of Two-Dimensional Carbides and Nitrides (MXenes). Science 372 (2021) eabf1581. https://doi.org/10.1126/science.abf1581
2. G. Deysher, C. E. Shuck, K. Hantanasirisakul, N. C. Frey, A. C. Foucher, K. Maleski, A. Sarycheva, V. B. Shenoy, E.A. Stach, B. Anasori, Y. Gogotsi. Synthesis of Mo₄VAlC₄ MAX Phase and Two-Dimensional Mo₄VC₄ MXene with Five Atomic Layers of Transition Metals. ACS Nano 14 (1) (2020) 204−217. https://doi.org/10.1021/acsnano.9b07708
3. A. Levitt, D. Hegh, P. Phillips, S. Uzun, M. Anayee, J.M. Razal, Y. Gogotsi, G. Dion. 3D Knitted Energy Storage Textiles Using MXene-Coated Yarns. Materials Today 34 (2020) 17-29. https://doi.org/10.1016/j.mattod.2020.02.005
4. E. Pomerantseva, F. Bonaccorso, X. Feng, Y. Cui, Y. Gogotsi. Energy storage: the future enabled by nanomaterials. Science 366 (2019) eaan8285. https://doi.org/10.1126/science.aan8285
5. B. Anasori, M. R. Lukatskaya, Y. Gogotsi. 2D Metal Carbides and Nitrides (MXenes) for Energy Storage. Nature Rev. Materials 2 (2) (2017) 16098. https://doi.org/10.1038/natrevmats.2016.98
6. F. Shahzad, M. Alhabeb, C. B. Hatter, B. Anasori, S. M. Hong, C. M. Koo, Y. Gogotsi. Electromagnetic Interference Shielding with 2D Transition Metal Carbides (MXenes). Science 353 (2016) 1137-1140. https://doi.org/10.1126/science.aag2421
7. M. R. Lukatskaya, O. Mashtalir, C. E. Ren, Y. Dall’Agnese, P. Rozier, P.-L. Taberna, M. Naguib, P. Simon, M. W. Barsoum, Y. Gogotsi. Cation Intercalation and High Volumetric Capacitance of Two-dimensional Titanium Carbide. Science 341 (2013) 1502-1505. https://doi.org/10.1126/science.1241488
8. M. Naguib, M. Kurtoglu, V. Presser, J. Lu, J.-J. Niu, M. Heon, L. Hultman, Y. Gogotsi, M. W. Barsoum. Two-Dimensional Nanocrystals Produced by Exfoliation of Ti₃AlC₂. Advanced Materials 23 (37) (2011) 4248-4253. https://doi.org/10.1002/adma.201102306
9. P. Simon, Y. Gogotsi. Materials for Electrochemical Capacitors. Nature Materials 7(11) (2008) 845-854. https://doi.org/10.1038/nmat2297
10. J. Chmiola, G. Yushin, Y. Gogotsi, C. Portet, P. Simon, P. L. Taberna. Anomalous Increase in Carbon Capacitance at Pore Sizes Less Than 1 Nanometer. Science 313 (2006) 1760-1763. https://doi.org/10.1126/science.1132195