The Castano's research group focuses on tailoring the surface properties of materials by physical and chemical methods for engineering applications. The research areas are organized around four main fields: Nanotechnology, Surface Science, Functional Coatings, and Materials under Extreme Environments - Irradiation, Plasmas, and High Temperatures.
Industry Expertise (16)
Metalworking and Coatings Technology
Ceramics and Glass
Renewables and Environmental
Areas of Expertise (9)
Thin film deposition and characterization
Advanced Materials Characterization
Roberto Rocca Fellow (professional)
Roberto Rocca Fellowships are given exceptional university graduates who are citizens of Argentina, Brazil, Colombia, Indonesia, Mexico, Venezuela and Romania, and who will enter a Ph.D. program outside their own country or who have already begun their studies towards a Ph.D. at a university outside their own country.
Outstanding MSE Graduate Student Award at Missouri S&T (professional)
The materials science and engineering department at Missouri S&T recognizes every year a graduate student for his research and teaching outstanding contributions
NSF ASSIST/LEVERAGE Awardee 2019 (professional)
This award allows the faculty to participate in the Academic and Research Leadership Symposium (ARLS). The ARLS has two threads: (1) a faculty development thread, and (2) a research networking thread. The ARL Network promotes the discussion of ideas for improving networking among underrepresented minority faculty at a local and national level.
Virginia Commonwealth University: Postdoc, Chemical and Life Science Engineering
Research: “Synthesis of Heterogeneous Catalysts for Coupling Reactions”
“Advanced Nanomaterials Synthesis and Characterization”
Missouri University of Science and Technology: Ph.D., Materials Science and Engineering
Dissertation: “Cerium-based Conversion Coatings on Mg Alloys”
National University of Colombia: M.Sc., Engineering - Materials and Processes
Thesis: “Special Optical Effects of Titanium Dioxide Coatings on Mica”
National University of Colombia: B.Sc., Engineering Physics
Thesis: “Production and Characterization of TiN Coatings Prepared by Sputtering DC”
- Alpha Sigma Mu (Honorary Member)
- The Minerals, Metals & Materials Society (Member)
- The American Ceramic Society (Member)
Media Appearances (1)
New research could dramatically decrease the cost of producing pharmaceuticals
VCU NEWS online
Researchers in the Virginia Commonwealth University College of Engineering and departments of Physics and Chemistry have discovered ways to accelerate chemical reactions that could dramatically decrease the costs of producing pharmaceuticals.
Multifunctional cerium-based nanomaterials and methods for producing the same
Embodiments relate to a cerium- containing nano-coating composition , the composition including an amorphous
matrix including one or more of cerium oxide , cerium
hydroxide , and cerium phosphate ; and crystalline regions including one or more of crystalline cerium oxide , crystal
line cerium hydroxide , and crystalline cerium phosphate . The diameter of each crystalline region is less than about 50 nanometers .
MECHANICAL SYSTEMS DESIGN - EGMN 300 - Fall 2017 - 2018
Basic principles of applied mechanics and materials employed for the design of machine elements and mechanical systems; state of stress, deformation and failure criterion is applied to bearings, brakes, clutches, belt drives, gears, chains, springs, gear trains, power screws and transmissions.
Special Topic: Functional Coatings - EGMN 691 Summer 2018
This graduate level course introduces basic and advanced concepts in the field of surface coatings physics and chemistry. The topics will include coating deposition methods and the relationship of the physical and chemical properties explaining the macroscopic functionality of the materials. Special emphasis will be placed in corrosion protection, wear, superhydrophobicity, optical, and electromagnetic applications.
Special Topic: Materials Synthesis Lab - EGMN 691 - Spring 2019
This graduate course covers the basic principles of materials synthesis. From the lab perspective, the design of materials from either solid, liquid, gas, or plasma phase will be presented targeting final properties and applications. Three basic modules are discussed in detail to target the Synthesis Processes for Metals, Ceramics, Polymers, and Composites of 1) Bulk Materials , 2) Nanomaterials, and 3) Thin Films
Selected Articles (4)
Combining the recyclability of heterogeneous catalysts with the high activity of ligated homogeneous catalysts for the production of complex organic molecules is a cardinal goal of catalyst development. We have investigated the activity of ultra-fine Pd clusters bound to vacancy defective sites in graphene and found that the defective graphene both serves as a support to stabilize the recyclable catalyst, and also functions as a ligand enhancing the catalytic activity. In this paper, we report computational and experimental results that provide insights into the nature of the interfacial interactions between metal nanoparticles and defect sites on the graphene surface. Theoretical investigations reveal that while the vacancy/void sites on the graphene surface strongly bind to the metal clusters providing enhanced stability against leaching, graphene also serves as a reservoir of electron density that effectively reduces the activation energy of specific steps within the catalytic cycle. Furthermore, multiple experimental methods were used to unambiguously demonstrate that these cross-coupling reactions are occurring at the Pd/G catalyst surface.
Cerium-based oxide compounds are known for their wide range of applications in catalysis, corrosion prevention, electrochemical cells, photocatalysis, UV absorbers, biomaterials, microelectronics, optical devices, thermal coatings, and glass abrasives. The technological applications of these materials are possible due to a combination of the electronic structure of Ce and the size effects at the nanoscale. In particular, reversible transformation between the Ce(III) and Ce(IV) oxidation states on the surface of cerium oxides is critical to the functionality and potential uses of the materials. In this paper, the main technological applications of cerium-based oxide coatings are reviewed based on the work done to date. Special interest is placed on the emerging trends.
The evolution of microstructure and chemistry was studied for AZ31 Mg alloy substrates after grinding, acid cleaning, alkaline cleaning, cerium-based conversion coating (CeCC) deposition, and phosphate post-treatment. Grinding provided a homogeneous surface with comparable amounts of oxides and hydroxides species. After acid treatment, this layer was ~ 90 nm thick, predominantly composed of oxide species (~ 85 at.%), and Mg deficient compared to the alloy chemistry. Treatment in an alkaline solution selectively removed Al species and produced a porous hydroxide layer. Immersion of the substrate in a cerium solution resulted in spontaneous deposition of a CeCC. Analysis revealed that the as-deposited CeCC contained more than 60 at.% Ce(IV) species with nodular CeO2 nanocrystals embedded in an amorphous Ce(III)-rich matrix. After post-treatment in a phosphate solution, the coating was transformed into a dense, homogenous layer with fewer cracks than the as-deposited CeCC and the content of Ce(IV) species decreased to ~ 50 at.%. The post-treated CeCC had a nodular morphology and contained a mixture of CeO2/CePO4•H2O nanocrystal species embedded in an amorphous matrix. Electrochemical results of as-deposited and post-treated CeCCs indicated an increase of ~ 4 × in the corrosion resistance compared to ground uncoated AZ31 Mg alloys in a 0.05 M NaCl electrolyte. However, the impedance spectra of the CeCCs at low frequencies showed that post-treated coatings not only have higher impedance but may also act as a barrier for active corrosion species.
In general, each of the five processing steps had functionalized the surface of the AZ31 Mg alloy by reducing active cathodic sites, modifying the chemistry, changing the structure or forming protective layers. Understanding the coating evolution has provided insights on the surface preparation of Mg alloys and a basis for studying the response and evolution of these coatings after exposure to corrosive and ambient environments.
Nanostructured cerium-based coatings on AZ31 Mg alloy substrates exposed to sunlight under ambient conditions had an ∼30% increase in Ce(III) species compared to unexposed coatings as measured by X-ray photoelectron spectroscopy. A decrease in film cracks and shift in bandgap from 2.5 eV to 2.7 eV were also measured. Visible changes in color, from yellow to translucent, with exposure were also observed and suggest that cerium-based coatings are reduced by light exposure in humid environments.