In summer 2019, I researched in the synthesis of noble-metal nanocrystals for energy applications through the Research Experience for Undergraduates (REU) Program at Georgia Tech. With Dr. Younan Xia as my advisor, I successfully synthesized high-quality platinum (Pt) nanobars with tunable aspect ratios in collaboration with a graduate student. Using FTIR spectroscopy, I confirmed that carbon monoxide was produced from the decomposition of the solvent at high temperature. This molecule then effectively functioned as a capping agent for Pt {100} facets and facilitated the formation of Pt nanobars. My analyses of transmission electron microscopy (TEM) images enabled me to propose a mechanism to account for the symmetry breaking involved in the formation of Pt nanobars. By the end of the 10-week program, I gathered data for both oral and poster presentations detailing my findings at the research symposia at Georgia Tech and Agnes Scott College, and the 2019 Gulf Coast Undergraduate Research Symposium at Rice University. I am currently in the process of writing the manuscript for publication. Continuing to work in the Xia group during my senior year, I will evaluate the catalytic properties of Pt nanobars for the methanol oxidation reaction. Throughout my research experience in noble-metal nanocrystals, I developed an interest in materials chemistry, with a concentration in nanomaterials synthesis, through which I can address a multitude of environmental challenges. 

Carbon Monoxide-Mediated Synthesis of Pt Nanobars and A Mechanistic Understanding of Their Symmetry Breaking

Nguyen, Quynh N¹, Chen, Ruhui², Xia, Younan^{2, 3} 

1. Department of Chemistry, Agnes Scott College, Decatur, Georgia
2. School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
3. The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia

Abstract

Despite the notable progress in controlling the shapes of noble-metal nanocrystals, it remains a grand challenge to synthesize nanocrystals with less symmetric structures relative to their cubic lattice. Among the noble-metal nanocrystals taking various shapes with reduced symmetry, Pt nanobars have attracted much interest because of their asymmetric growth during the synthesis and the anisotropic structure as compared to Pt nanocubes. There are only a few reports on the synthesis of Pt nanobars with limitation in controlling aspect ratio and lack of a well-resolved mechanistic understanding of their anisotropic growth. Here we report a facile route to high quality Pt nanobars, in which N,N-dimethylformamide (DMF) was used as a reducing agent in the presence of poly (vinyl pyrrolidone) (PVP) as a stabilizer and a mild reducing agent. The aspect ratio of the Pt nanobars could be tuned by simply varying the amount of Pt precursor. Arising from the decomposition of DMF, CO served as a capping agent on Pt {100} facets, which facilitated the formation of Pt nanobars. The anisotropic growth of Pt nanobars was induced by particle coalescence during the early stage of a synthesis, followed by localized oxidative etching and further preferential growth by atomic addition.

Acknowledgement– This work was supported by a grant from the National Science Foundation REU No. CHE-1560335. TEM imaging was performed at the Georgia Tech’s Institute for Electronics and Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the National Science Foundation No. ECCS-1542174.

Project 2:

Anomalous redox behavior of bis(serinato)copper(II) complex and comparison to closely related bis(homoserinato)copper(II) complex: An update

Nguyen, Quynh N.,¹ Venable, T. Leon ¹

1. Department of Chemistry, Agnes Scott College, Decatur, Georgia 30030, United States

Abstract

Despite being a vital nutrient and having important roles in biological processes, unbound copper ions are toxic when acting as a redox catalyst in the formation of free radicals, which in turn may lead to the oxidation of biologically active molecules. As part of our extended studies on the synthesis and behavior of Cu(aminoacidato)₂ complexes, we have continued to investigate the anomalous redox behavior of the cis-bis(L-serinato)Cu complex, which is readily prepared from the reaction of [Cu(CH₃COO)₂•H₂O]₂  and the appropriate amino acid. This bis(L-serinato)Cu complex is distinctively different from all other known Cu(aminoacidato)₂ complexes in that it undergoes a spontaneous redox reaction upon exposure to atmospheric oxygen to yield reduced Cu(I) in the form of Cu₂O. The identity of the oxidized species in the reaction has been elusive. This unusual redox reaction was determined to be a multi-step process. Under slightly acidic conditions in the presence of atmospheric O₂, a significant shift in λ_max of the bis(L-serinato)Cu solution (from 625 nm to 704 nm) occurred with no evidence of Cu₂O formation. In turn, this solution rapidly reacts with O₂bubbled into the solution to yield the previously described red Cu₂O. From a comparison with bis(L-homoserinato)Cu, the primary OH functional group on L-serine was not shown to be the key to the anomalous behavior of bis(L-serinato)Cu; the attempted oxidation of the closely related trans-bis(L-homoserinato)Cu did not occur under the same conditions. We will also report on attempts to compare the bis(cysteinato)Cu complex, which has a primary thiol group, to the bis(L-serinato)Cu with a primary alcohol group.

Nguyen, Q. N; Venable, T. L.; “Anomalous redox behavior of bis(serinato)copper(II) complex andcomparison to closely related bis(homoserinato)copper(II) complex: An update.” Southeastern Regional Meeting of the American Chemical Society (SERMACS), Savannah, GA, October 2019 (Poster presentation)

Nguyen, Q. N.; Chen, R.; Xia, Y.; “Carbon monoxide-mediated synthesis of Pt nanobars and amechanistic understanding of their symmetry breaking.” Research Experience for Undergraduate (REU) Symposium at Georgia Institute of Technology, Atlanta, GA, July 2019 (Poster and oral presentation)

Nguyen, Q. N.; Caven, C.; Romero, S. C.; Venable, T. L.; “Anomalous redox behavior of bis(serinato)copper(II)complex and comparison to closely related bis(homoserinato)copper(II) complex.” Spring Annual Research Conference (SpARC), Agnes Scott College, Decatur, GA, April 2019 (Poster presentation)

Inorganic Chemistry

Nanotechnology

Nanomaterials

Materials Science

Electrochemistry

I. Introduction courses:

CHE-150 INTRODUCTION TO CHEMISTRY 

This course delves into the world of atoms and molecules in order to study the structure of matter and the changes it undergoes. The course will provide an introduction to the field of chemistry. Topics include atomic and molecular structure, stoichiometry, acids and bases, enthalpy, and equilibrium. In addition, contemporary problems and applications of these topics may be explored. Examples may include atomic and molecular structure relevant to the design of new material such as memory metals; stoichiometry as a means of achieving green chemistry; acids and bases in the context of biochemical and environmental reactions; enthalpy in the context of energy generating fuels; and equilibrium and its role in energy storing batteries.

INTRODUCTION TO BASIC CHEMICAL LABORATORY TECHNIQUES

This lab course focuses on the experimental methods in basic scientific measurements, elementary reactions and analysis arranged around a theme such as forensics or the environment.

II. Inorganic Chemistry:

CHE-220 FOUNDATIONS OF INORGANIC AND PHYSICAL CHEMISTRY

This foundation course focuses on introductory aspects of inorganic and physical chemistry. Topics may include fundamental chemical reactions, nuclear structure and radioactivity, molecular shapes, trends as seen in the periodic table, equilibrium, gas laws, molecular collision theory, the laws of thermodynamics, phases, reaction rates and reaction mechanisms. To illustrate the role of chemistry in fundamental physical and chemical behaviors, examples are chosen from a variety of areas including environmental, medical, and forensic applications.

CHE-220L FOUNDATIONS OF INORGANIC AND PHYSICAL CHEMISTRY LAB

Labs introduce students to the analysis and interpretation of observations. This course will also illustrate fundamental principals of chemistry including: reactivity of main group and transition metals; bonding and its relation to behavior; solution behavior; gas laws; heat capacity and enthalpy changes; and kinetics of reactions.

CHE-270 FOUNDATIONS OF INORGANIC AND BIOINORGANIC CHEMISTRY  

This foundation course in inorganic chemistry examines the behavior of the elements in an effort to identify and explain patterns on the periodic table. The course focuses on the approximately 28 elements with known roles in biochemical systems including iron, copper, zinc, Na+/K+ , Mg+2, and Ca+2. Topics include the toxicity of environmental pollutants and the often surprising toxicity of nutritionally required elements such as iron and copper. Recent discoveries and case studies are used to explain biochemical selectivity in a wide variety of systems; plant, animal and archaea.

CHE-370 MODERN INORGANIC CHEMISTRY

This in-depth course introduces current theories of bonding, group theory and molecular symmetry, molecular and solid state structures, magnetism, stereochemistry and reaction mechanisms involving both main group elements and transition metals. Classes of molecules will include main group, metal, and hybrid clusters and the emerging field of molecular super-atoms. Descriptions of the bonding in such molecules will include Wade’s Rules for clusters and molecular orbital descriptions of exotic molecules (e.g. the interstellar CH5 + and interstitial structures (e.g. He@C60).

CHE-375 MODERN INORGANIC CHEMISTRY LABORATORY

This in-depth lab course focuses on the synthesis and spectroscopic characterization of inorganic and organometallic compounds and the correlation of structures with contemporary crystal field and ligand field theories. Target molecules will include examples of cluster structures such as organotransition metal metallocarboranes and their precursors along with traditional transition metal complexes. Synthesis techniques will focus on oxygen-free and microscale reactions. Students will prepare publication ready lab reports that include budgetary and safety discussions.

III. Analytical Chemistry:

CHE-230 ANALYTICAL CHEMISTRY I

This foundational course centers on quantitative chemical analysis. Students will study chemical equilibria including acid-base chemistry, buffers, and solubility as well as various methods used to measure chemical species in solution such as titrimetry, electrochemistry, absorption spectroscopy and chromatography.

CHE-330 ANALYTICAL CHEMISTRY II

Advanced study of chemical instrumental analysis with an emphasis on understanding the major instrumental methods chemists use to study chemical phenomena. Techniques include absorption and emission spectroscopy, Fourier-transform infrared spectroscopy, mass spectroscopy, nuclear magnetic resonance spectroscopy, chromatography, and electrochemistry.

CHE-335 ADVANCED ANALYTICAL CHEMISTRY LABORATORY

This laboratory course is a hands-on experimental experience investigating an original chemical analysis problem using a number of instrumental methods. The problems may be chemical, environmental, or biochemical in nature depending on student interests. Students will identify a scientific question, and formulate an experimental design and conduct experiments utilizing two or more departmental instruments such as the NMR, FTIR, GC, GC-MS, HPLC, FAAS. Students will also gain experience obtaining and preparing samples, analyzing and interpreting data, and drawing valid conclusions based on experimental results.

III. Organic Chemistry:

CHE-240 ORGANIC CHEMISTRY I

The systematic study of the chemistry of organic compounds with emphasis on theories of structure and reactivity. Specific topics include basic organic molecular structure and bonding, isomerism, stereochemistry, molecular energetics, substitution and elimination reactions, and reactions of biologically relevant functional groups.

CHE-240L ORGANIC CHEMISTRY LABORATORY

Introduction to fundamental experimental techniques of carbon‐based molecules, including organic synthesis, purification and separation techniques, and theory and interpretation of infrared and nuclear magnetic resonance spectroscopy.

CHE-340 ORGANIC CHEMISTRY II

This course is a continuation of CHE-240 and it continues the systematic study of the principal functional groups in organic compounds. Specific topics include the theory and chemical reactivity of conjugated and aromatic systems, the fundamentals of organic synthesis, and reactions of biologically relevant functional groups.

CHE-340L ORGANIC CHEMISTRY II LABORATORY 

Project‐based synthesis based laboratories including functional group analyses and reactions. Use of advanced instrumentation including nuclear magnetic resonance, infrared spectroscopy and GC‐MS are required for analysis of project results.

IV. Physical Chemistry:

CHE-260 PHYSICAL CHEMISTRY I 

This course is a continuation of the introduction to physical chemistry that began in CHE-220. Topics will include general principles of thermodynamics and equilibria, kinetics and solution dynamics, and an introduction to quantum mechanics as applied in chemistry and biochemistry. More specifically, students will study such topics as the dependence of Gibbs energy on temperature and pressure, mixtures and solutions, theories of reaction rates, the Schrodinger equation, molecular orbital theory, and a brief introduction to symmetry.

CHE-365 PHYSICAL CHEMISTRY LABORATORY

This is an in-depth laboratory based course that will allow students to study key experimental physical chemistry concepts, gain experience with equipment and instrumentation used in physical chemistry research, and increase their understanding of fundamental physical chemistry topics through hands on experiments. Topics will span the fields of thermodynamics, kinetics and quantum mechanics and students will use a variety of scientific instruments and equipment. A significant amount of time will also be spent on data analysis and calculations.

IV. Biochemistry:

CHE-300 INTRODUCTION TO BIOCHEMISTRY

Fundamentals of biochemistry, including structure and function of biomolecules, enzyme kinetics, bioenergetics, catabolic and anabolic pathways and regulation of biochemical processes. Fundamental biochemical laboratory techniques including spectroscopy, enzymology, chromatographic separations, and protein detection methods.

V. Advanced and Graduate-level Courses:

CHE-410 DIRECTED READING

Directed reading courses are open to qualified juniors and seniors to pursue reading outside a program’s listed courses.

CHE-440 DIRECTED RESEARCH

Directed research courses are open to junior and senior majors to work with a faculty member on a project related to particular field of intellectual or artistic interest.

CHE-450 INTERNSHIP

For juniors and seniors who want a more-focused academic component to accompany their internship, the independently designed 450 may be an option.

CHE-4803 NANOSCIENCE – Science and Technology on the Nanoscale (Georgia Institute of Technology)

This course is mainly designed for graduate students and juniors/seniors in the school of chemistry  and biochemistry. It covers the basic principles and recent advances in representative areas of nanoscale science and technology. The selected topics should also be appropriate for graduate and undergraduate students from other academic units, including physics, chemical engineering, materials science and engineering, biomedical engineering, electrical engineering, and mechanical engineering. The focus will be placed on the chemistry and physics of materials, structures, and surfaces with characteristic feature sizes below 100 nm: for example, when does size matter? how do we engineer the properties of material, structures, and surfaces by controlling the feature size? what is the ultimate limit for size control? how do we synthesize nanomaterials, fabricate nanostructures, and generate nanoscale patterns? what are the scientific and technical challenges in these areas? what are the unique opportunities of nanomaterials in catalysis, electronics, photonics, energy conversion, and biomedicine?

Reflecting on my experience as a member of “The Electras” team in this class, my role in our team changed from a follower to an integrator and a facilitator through engaging with our group discussion. When I first started the class, I thought I was going to spend the entire year learning physics concepts, solving problems and taking tests. However, I quickly found out that that there was so much more to it. I love that the class implemented the “Team-Based Learning” concept in every lecture. It helped me learn how to work effectively as a member of a team, as well as express my own idea as a future leader. I was shy and afraid to say what I thought at first. However, my teammate always encouraged me to engage in the discussion and asked me what I think about the questions. Thanks to them, I started to actively participate in group discussion, answering question and explain my ideas to others. Also, I figure one of my strength is being a good facilitator. Being a little OCD myself and love the feeling of getting things done, I always make sure that my group stay on top of our tasks, concentrate on our work and answer questions to the best of our ability. I think the fact that I made sure everyone understands and agrees with the final answer during the TBL team quiz would be a way that I positively contributed to our group. Moreover, when I do my work, I am very meticulous about how it is done and the quality of which it is done. I like to make sure things are thoroughly checked over before submitting them. Thus, I would usually write and check our answer before we presented to the class.

In spite of my strengths, I also have weaknesses when it comes to working with others. Thanks to the feedback that I received from other members, I was able to understand my weakness and try my best to fix it. I realized that for future discussion, I should be a little more open-minded to suggestions. There are times where I think my idea is best but the reality of it is that I am wrong. Being wrong is something I don’t usually like to admit. I think that being able to better take in everyone’s ideas is something that I need to improve on. Working in a team is truly a group effort in which everyone has the potential to bring something to the table. All of members of the group deserve to have their voice heard and their options considered before coming to a final decision. I remember the first time we were required to take the quiz on a new chapter as a group; I didn’t like this idea at first because I thought there would be conflicts arising from people having lots of opinions. However, after the first quiz discussion together, I found it very useful to listen to other members’ ideas. Nevertheless, I was not able to be a better listener until I read two teammates’ comment through CATME evaluation because I had always thought that I listened to others. Their feedback helps me pay more attention to what they are saying and respect their comments. For the quiz that happened a week after that, I told myself not to dominate the conversation and started to listen. I found that other members’ ideas were amazing and were able to learn from them. 

There were a lot of patterns that contribute to our group successes. First and foremost, our group members played very active roles toward solving the problem sets during our teamwork and maintaining good quality of work. This means we can ensure high levels of efficiency. Especially Julia, a member in our group, has strong organizational skills and problem-solving abilities, as well as the ability to put ideas in a logical way. When we discuss the question, she always takes the initiative to write our ideas on a board and present it in a more coherent way. Since all group members always contribute great ideas, our group discussion is always like a brainstorming activity which allows us to think in an unconstrained way. However, one issue we encountered is that group members easily reject each other’s opinion because it is difficult for each of us to fully explain and back up our idea. There was one instance very early on in the first quiz where one team member made a suggestion and the other two members immediately disagreed with it without trying to understand what she meant. When we scratched off the answer sheet, it turned out that the first member’s answer was right. We realized that we may have rejected the idea too quickly and should have listened to her explanation. I think this was an instance where we should be more patient and value others’ ideas. We are still working on this aspect and I hope that every member’s idea will be heard and considered in future quizzes. 

Working with five other members in this class, I have grown and learned a lot of helpful lessons that I can apply to other classes and my future career. It is important for a group to have shared goals and for each member to have a clear role. For my future group work, it would be helpful to have a team contract to ensure that everyone in the grouphas the same expectations of each other. This will avoid frustration and misunderstandings during the project. Being able to see the rules that all group members generated and agree together every time we have group work will remind us of our roles and staying on top of our tasks. The most important lesson is being able to analyze team feedback and changing behaviors to help facilitate teamwork. I enjoy the process after comprehensively reflecting the participation of our team’s collaborative processes through CATEME and listening to others’ feedback. It helped me to know what my weakness and strengths are and improve myself to be a better teammate. In future project, I will make sure to give others constructive feedback so that we can move forward as a team. For my future goal, I want to work in medical field and these collaboration skills are no doubt my most valuable assets that I would bring along when working with other professionals. 

Throughout this class, working as a group to share our opinions, rethink and understand the lecture contents helps correct my understanding of the topics and improve my ability of critical thinking. The experience has trained me to have good teamwork spirit and to cooperate with other students. I can apply these skills not only in the academic setting but also in my future career. After every TBL team quiz, there is always a reflection question “What makes your team the best?” Our group’s only answer is that we always stay optimistic, listen to each other’s opinion and come to an agreement at the end of the discussion. As the end of the semester rolls around, I believe we have not only met the goals that we set, but I would say we exceeded them. Our group always have clear objectives, defined roles and good communication to do work efficiently. In just three months, our group members all become closer as friends which makes our teamwork even stronger. At the end of the day, I am content with all the work we have accomplished as a group.