• The low- and high-energy tails of the phonon density of states (PDOS) of transition-metal nanoparticles is enhanced with respect to that of their bulk counterparts. For particles in the sub-nanometer scale, we propose a rationale for this fact based on ab initio calculations of their charge density and of the frequency and displacement pattern of [...]

  • Our paper “Rational Design of Competitive Electrocatalysts for Hydrogen Fuel Cells” has been featured in numerous reputable web portals specialized on scientific and technological news, such as Science Daily, Green Design and Manufacturing, Nanotechnology Today, World of Chemicals, Laboratory Equipment, PhysOrg, PressNews.org, AZoCleantech, and dozens of other on-line publishers. See below:

  • Fuel Cell Bulletin has published in its “News” section a short description of our work and pointed out that by creating the proposed system, more hydrogen chemical energy will be converted in to electric one and cost of fuel cells (that currently are very expensive) will be significantly reduced. The Fuel Cell Bulletin is the [...]

  • The Defense Tech Brief, the largest circulation design engineering magazine, has published a short article “Sandwich-Like Structures for Efficient Hydrogen Fuel Cells” about our recent findings on competitive electrocatalysts for hydrogen fuel cells, which demonstrate that better and less expensive electrocatalysts can be designed rationally: J. Phys. Chem. Letts. 3, 463 (2012)

  • UCF Professor Sergey Stolbov and postdoctoral research associate Marisol Alcántara Ortigoza Create More Efficient Hydrogen Fuel Cells by making gold and palladium better suited for the ORR reaction. Mar. 15, 2012 — Hydrogen fuel cells, like those found in some “green” vehicles, have a lot of promise as an alternative fuel source, but making them [...]

  • The International Business Times, one of the world’s leading business news organizations, has published an article entitled “More Efficient Hydrogen Fuel Cells Developed by Researchers” about our new approach to rational design of cost-effective catalysts for hydrogen fuel cells published in Journal of Physical Chemistry Letters ( J. Phys. Chem. Letts. 3, 463 (2012)) http://au.ibtimes.com/articles/318299/20120323/more-efficient-hydrogen-fuel-cells-developed-researchers.htm#.Ue-Rj403uSo

  • An article “Researchers seek to improve efficiency of hydrogen fuel cells” featuring Prof. Stolbov and my work has been published in “The Engineer” the only magazine serving the United Kingdom’s engineering technology community since 1856. Reference:  http://www.theengineer.co.uk/energy-and-environment/news/researchers-seek-to-improve-efficiency-of-hydrogen-fuel-cells/1012018.article  

  • The Advanced Fuel Cell Technology magazine, published by Seven Mountains Scientific, Inc., has devoted to our work an article entitled “Rational Design Can Improve Fuel Cell Efficiency” highlighting that our rationally designed materials may improve both efficiency and cost-effectiveness of fuel-cells cathode catalysts, outperforming the best platinum-based catalysts to date. Reference: http://7ms.com/fct/online/2012/03/rational-design-can-improve-fuel-cell-efficiency.html  

  • [J. Phys. Chem. Letts. 3, 463 (2012)] The hydrogen fuel cells convert chemical energy stored by hydrogen molecules into electric energy and the only product of this reaction is clean water. However, large-scale practical applications of these very promising sources of clean renewable energy are still restricted by unacceptably high cost of platinum-based catalysts that are [...]

  • [Phys. Rev. B 84, 245438 (2011)] As experimentalist design better and better techniques to investigate nanoscale systems, anomalous electronic and thermodynamic properties for nanoparticles (NPs) continue being reported. Yet, despite several years of investigations, the origin of these effects was, until recently, still heavily debated. Among the inexplicable “anomalies”, I have focused on understanding those reported [...]

  • [J. Phys.: Condens. Matter 24, 104026 (2012)] Phenomena at the nano-scale are subjects of wide interest because of their fundamental and technological significance. Structure characterization, stability and thermal properties of nanoparticles (NPs) are, in their own right, topics of intensive research, and today’s physicists use state-of-the-art experimental and computational techniques to unravel them. In reference [1], [...]

  • [Phys. Rev. B 82, 085405 (2010)] Understanding materials growth has been a subject of interest already for several decades. The dynamical processes involved in these phenomena in fact bear importance for several aspects of material science; metal oxidation rates and functionality (catalytic, magnetic, etc.) of supported heterogeneous materials when complex structural pattern formation become important, for [...]

  • [Phys. Rev. B 77, 195404 (2008) and Contemporary Physics: Proceedings of the International Symposium by Jamil Aslam, Faheem Hussain, Riazuddin; Published by World Scientific (2008)] It is quite clear now that small nanoclusters necessarily have physical and chemical attributes that are distinct from those of their pure bulk counterparts, features that are of course attractive to achieve specific [...]

  • [Phys. Rev. B 78, 195417 (2008) and  J. Phys.: Condens. Matter 21, 474226 (2009)] This work focuses on understanding the performance of clean energy conversion nanodevices, proton exchange membrane fuel cells (PEMFCs) in particular. Operation of the anode in these devices consists of splitting hydrogen molecules into protons and electrons and Pt atoms on the anode catalyze such process. [...]

  • [Phys. Rev. B 81, 115465 (2010)] Controlling and exploiting self-ordering of materials requires us to understand the structure at the atomic level and the mechanism that drives the nanoscale self-assembling. The result of adsorbing nitrogen on the Cu(001) surface constitutes one example of nanoscale self-ordering as it forms squared 6×6 nm2 N-patches on top of the [...]

  • [J. Phys. Chem. A, 115 (25), 7291 (2011)] The coupling between molecules and metallic surfaces has attracted much interest in the last three decades because of the insight it provides into chemisorption and diffusion processes. The interactions present when carbon monoxide (CO) is absorbed on metals surfaces are of particular importance since they influence chemical reactions of [...]

  • This work follows in many ways that performed for the adsorption of CO on Cu(001) [1]. Yet, it opened a wealth of new insights about the way we characterize CO adsorption. The interest on CO adsorption on Ag surfaces lies on the ability of Ag(110) to catalyze the formation of CO2 and CO3 from O2 [...]

  • [J. Phys.: Condens. Matter 20, 224009 (2008) and Phys. Rev. B 79, 125432 (2009)] Nailing down the essentials to optimally catalyze a desired reaction is still a very challenging problem. Not surprisingly, although most production processes in industry are catalyzed, most chemists and engineers are restricted to trial and error when searching for the proper catalyst. The interest on [...]

  • [Phys. Rev. B 72, 174416 (2005) and Phys. Rev. B 74, 226401 (2006)] Developing quantum computing and increasingly smaller memory storage devices has led intense research into the properties of nanoscale magnets, including quantum single-molecule magnets (SMM) and arrays of ferromagnetic nanodots. This goal, however, faces several challenges. One of them is the ever-present inter-magnet interactions, which are directly responsible [...]

Latest Projects

The low- and high-energy tails of the phonon density of states (PDOS) of transition-metal nanoparticles is enhanced with respect to that of their bulk counterparts. For particles in the sub-nanometer scale, we propose a rationale for this fact based on ab initio calculations of their charge density and of the frequency and displacement pattern of their vibrational modes. I find that the radial breathing and non-radial vibrations — analogous to [...]

[J. Phys. Chem. Letts. 3, 463 (2012)] The hydrogen fuel cells convert chemical energy stored by hydrogen molecules into electric energy and the only product of this reaction is clean water. However, large-scale practical applications of these very promising sources of clean renewable energy are still restricted by unacceptably high cost of platinum-based catalysts that are used for the energy conversion. It is thus not surprising that during the past decade [...]

[Phys. Rev. B 84, 245438 (2011)] As experimentalist design better and better techniques to investigate nanoscale systems, anomalous electronic and thermodynamic properties for nanoparticles (NPs) continue being reported. Yet, despite several years of investigations, the origin of these effects was, until recently, still heavily debated. Among the inexplicable “anomalies”, I have focused on understanding those reported for Pt NPs, which include negative thermal expansion from 100 to 700 K, low mean-squared [...]

[J. Phys.: Condens. Matter 24, 104026 (2012)] Phenomena at the nano-scale are subjects of wide interest because of their fundamental and technological significance. Structure characterization, stability and thermal properties of nanoparticles (NPs) are, in their own right, topics of intensive research, and today’s physicists use state-of-the-art experimental and computational techniques to unravel them. In reference [1], however, I have directed a study that shows how thoughtlessly application of certain approximations is [...]

[Phys. Rev. B 82, 085405 (2010)] Understanding materials growth has been a subject of interest already for several decades. The dynamical processes involved in these phenomena in fact bear importance for several aspects of material science; metal oxidation rates and functionality (catalytic, magnetic, etc.) of supported heterogeneous materials when complex structural pattern formation become important, for example. The diffusivity of adatom clusters is long recognized as a critical controlling factor in [...]

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