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Congratulations to Jaejung (JJ) Kim: the recipient of GT-PURA award
November 2022
Congratulations JJ for winning the Spring 2023 President's Undergraduate Research Award (PURA). She will be working on the following project: shining light on silver nanocubes for detecting toxins by spectroscopic fingerprinting.
Congratulations to Dr. Qin: Promotion to Full Professor
April, 2022
Dr. Qin has been promoted to full professor in the School of Materials Science and Engineering. She also holds an adjunct appointment in the School of Chemistry and Biochemistry. She is a recipient of the GT-Class of 1940 W. Roane Beard Outstanding Teacher Award (2020), GT-Provost Teaching and Learning Fellow Award (2018), GT-Geoffrey G. Eichholz Faculty Teaching Award (2018), 3M Non-Tenured Faculty Award (2015), and GT-CETL/BP Junior Faculty Teaching Excellence Award (2015).
Publication in Accounts of Materials Research
February, 2022
Silver nanocrystals embrace fascinating properties for a wide variety of applications, but their performance tends to deteriorate because of shape instability arising from the dissolution of Ag atoms from high-energy sites such as edges and vertices. This issue can be addressed by framing the particle with a more stable metal M for the generation of a Ag@M core-frame nanocrystal. In addition to the improvement in shape stability, the inclusion of metal M expands the functionality and capability of the Ag nanocrystals.
Publication in ACS Nano: Tung-Han Yang
August, 2021
The ligands anchored to the surface of metal nanocrystals play an important role in controlling their colloidal synthesis for a broad spectrum of applications, but it remains a daunting challenge to investigate the ligand-surface and ligand-solvent interactions at the molecular level. Here we report the use of surface-enhanced Raman scattering (SERS) to extract structural information about the binding of poly(vinylpyrrolidone) (PVP) to Ag nanocubes, as well as its conformational changes in response to solvent quality.
Congratulations to Dr. Shi (Shirley) Shi
June 28, 2021
Shirley successfully defended her thesis work: Bifunctional Metal Nanocrystals for Catalyzing and Reporting on Chemical Reactions by Surface-Enhanced Raman Scattering. She is ready for the next chapter of her life!
Publication in ACS Nano Article: Xiaojun Sun
July, 2016
We report a facile synthesis of Au-based cubic nanoboxes as small as 20 nm for the outer edge length, together with well-defined openings at the corners and walls fewer than ten atomic layers (or <2 nm) in thickness. The resultant Au nanoboxes exhibit strong plasmonic absorption in the near-infrared region, consistent with computational simulations.
ACS Fall Meeting 2016 in Philadelphia: Yiren Wu
August, 2016
Yiren represented the group to give two oral presenations on August 20th in the session of "Nanoparticles: Synthesis, Characterization & Their Application in Catalysis" (COLL 12) and "Plasmonic Colloidal Nanostructures: From Creation to Applications" (COLL 113). She also presented a poster.
Publication in CPublication in Chemistry of Materials Article: Chia-Wei Wanghemistry of Materials Article: Chia-Wei Wang
September, 2016
We report a simple and versatile system for generating highly concentrated H2O2 on the surface of nanoparticles through enzymatic oxidation of glucose. It involves immobilization of glucose oxidase, a negatively charged enzyme, on the surface of a positively charged metal nanoparticle via electrostatic attraction. Upon the introduction of glucose at a concentration of 1.7 mM, this system is able to produce enzymatic H2O2 on the surface of the nanoparticle, with oxidation power equivalent to that of aqueous H2O2 at a concentration of 5 M when it is directly added into the reaction solution.
Congratulations to Yiren Wu
November, 2016
Yiren successfully defended her thesis proposal -- Colloidal Hybrid Nanocrystals: Syntheses, Properties, and Applications.
Thank You for Being a Great Teacher
December, 2016
In appreciation of her teaching style and dedication to helping students learn in MSE 4330 (Fundamentals of Nanomaterials and Nanostructures) and MSE 2001 (Principles and Applied Engineering Materials), Dr. Qin received three certificates from "Thank a Teacher Program" at Georgia Tech.
Publication in ChemNanoMat Article: Yiren Wu
February, 2017
We report the synthesis of bifunctional Ag@SiO2/Au nanoparticles with an “islands in the sea” configuration by titrating HAuCl4 solution into an aqueous suspension of Ag@SiO2 core-shell nanocubes in the presence of NaOH, ascorbic acid, and poly(vinyl pyrrolidone) at pH=11.9. The Ag@SiO2/Au nanoparticles can serve as a bifunctional probe to monitor the stepwise Au-catalyzed reduction of 4-nitrothiophenol to 4–aminothiophenol by NaBH4 and Ag–catalyzed oxidation of 4-aminothiophenol to trans-4,4’–dimercaptoazobenzene by the O2 from air in the same reaction system.
Congratulations to Albert Ahn
April, 2017
Jae Wan (Albert) Ahn received the 1st place award in the 5th Annual School of Materials Science and Engineering Undergraduate and Graduate Poster Session for his poster titled "Facet-Selective Growth of Gold on Silver Nanocubes" competing under the nanomaterials category.
Congratulations to Junki Kim
April, 2017
Junki Kim received the 1st place award in the 5th Annual School of Materials Science and Engineering Undergraduate and Graduate Poster Session for his poster titled "Gold-based Cubic and Cuboctahedral Nanoboxes with Plasmonic Absorption at Near-Infrared Wavelength" competing under the undergraduate research category.
Congratulations to Xiaojun Sun
April, 2017
Xiaojun Sun received the 2nd place award in the 5th Annual School of Materials Science and Engineering Undergraduate and Graduate Poster Session for his poster titled "Large Scale Synthesis of Silver-Enriched Nanoparticles and Their Applications" competing under the energy/electronic materials category.
MRS Spring 2017, Phoenix
April, 2017
Dr Qin, Xiaojun Sun, Junki Kim, and Zhiwei (Ryan) Zhang presented three oral talks and three posters at the MRS meeting.
Publication in Chemistry of Materials Article: Xiaojun Sun
April, 2017
This article describes a systematic study of the roles played by hydroxide in controlling the deposition of Au on Ag nanocubes for the fabrication of diversified Ag-Au bimetallic nanocrystals. The synthesis simply involves the titration of aqueous HAuCl4 into an aqueous suspension of Ag nanocubes in the presence of ascorbic acid, NaOH, and poly(vinyl pyrrolidone) at room temperature. The OH− ions from NaOH can affect the reduction kinetics of the Au(III) precursor in a number of ways and thereby the deposition pathways of the Au atoms.
Publication in ACS Nano Article: Yun Zhang
April, 2017
We report the development of an isocyanide-based molecular probe for in situ characterizing the overgrowth of a second metal on silver nanocrystal seeds in solution by surface-enhanced Raman scattering (SERS). As the first demonstration, we elucidate that the vibrational frequency of 2,6-dimethylphenyl isocyanide (2,6-DMPI) can serve as a distinctive reporter for capturing the nucleation of Pt on the edges of Ag nanocubes in the aqueous solution containing a Pt precursor, ascorbic acid, and poly(vinylpyrrolidone) under ambient condition.
Congratulations to Daniel Wang
May, 2017
Daniel Wang, a sophomore of GT-MSE, is the recipient of Hapman/Pentecost Scholarship.
Congratulations to Bonnie Vannatter
May, 2017
Bonnie Vannatter, a freshmen of GT-MSE, is the recipient of Georgia Tech Women in Engineering scholarship sponsored by Boeing.
Continuing Funding from NSF-MSN Program
May, 2017
Built upon the prior success of NSF project (CHE-1412006, 2014-2017), our proposal–“Understanding Heterogeneous Nucleation in Nanocrystal Growth with Molecular Probes”–was awarded by the National Science Foundation (NSF) through the Macromolecular, Supramolecular and Nanochemistry (MSN) Program (CHE-1708300, 2017-2020).
Congratulations to Daniel Wang: 2017 Fall PURA Award
June, 2017
Daniel has been selected as a recipient of a President’s Undergraduate Research Award (PURA) for Fall 2017. He become the 3rd PURA recipient from the Qin Lab.
Publication in Accounts of Chemical Research: Yiren Wu
June, 2017
In this Account, we use Ag nanocubes as an example to demonstrate the fabrication of Ag@M and Ag@Ag-M (M=Au, Pd, or Pt) nanocubes with a core-frame or core-shell structure by controlling the deposition of M atoms. A typical synthesis involves the titration of Mn+ (a precursor to M) ions into an aqueous solution containing Ag nanocubes, ascorbic acid, and poly(vinylpyrrolidone) under ambient conditions.
Congratulations to Xiaojun Sun
August, 2017
Xiaojun has successfully defended his thesis work -- Bimetallic Nanocrystals for Applications in Plasmonics and Catalysis -- on August 2, 2017. He is ready for his next challenge.
An introduction note from Dr. Qin before Xiaojun's defense:
"Good morning! Welcome to Xiaojun’s thesis defense! Xiaojun was born and raised in Shanghai. After he received his bachelor degree of materials science and engineering from Shanghai Jiaotong University, he came to the states and become the first year PhD student of Material Science and Engineering at Georgia Tech. I still vividly remembered the moment when I had my first meeting with Xiaojun in my office about four years ago. As you can imagine, I was trying very hard to recruit him to join the newly established Qin Lab with tons of my energy and enthusiasm. Xiao then was as calm as he is for now, but I can tell that he was excited about joining the Qin Lab. Before we both reached to a conclusion, I encouraged Xiaojun to perform a couple of survey experiments from which he demonstrated his competency. After we both happily signed the document, we started our journey together for the next four years. Looking back, I am very fortunate to have Xiaojun become my first PhD student! We have been working together side by side closely to achieve our goals and to establish the foundation for the Qin Lab. I am extremely grateful to his commitments on the assigned projects from very beginning to the end! It is also such a joy to witness the transformation of Xiaojun from a highly motivated individual to a matured and productive researcher! Today is very special for Xiaojun to mark his timeline! Let's welcome him to present his thesis work. Xiaojun, the floor is YOURS!!"
GT-MSE Seminar: Dr. Dong Qin
September, 2017
Enriching Silver Nanocrystals with a Second Noble Metal:
Silver is perhaps the best choice of material for plasmonics and related applications owing to its relatively low cost and favorable dielectric functions. Over the past two decades, significant progress has been made in the synthesis of Ag nanocrystals with controlled shapes and sizes to tailor their properties and thus optimize their performance in a range of applications. In particular, Ag nanocrystals have been prepared with sharp features on the surface to drastically augment their surface-enhanced Raman scattering (SERS) activity. However, the sharp features tend to vanish due to the high susceptibility of Ag towards oxidative etching. As another pitfall, Ag is limited in terms of catalytic application as it only shows activity towards oxidation reactions such as epoxidation, not reduction reactions.
One can address the aforementioned limitations of Ag nanocrystals by introducing a second noble metal (M) such as Au, Pd, or Pt to generate Ag-M bimetallic nanocrystals in the core-frame and core-shell structure. When the M atoms are selectively deposited on the edges of a Ag nanocrystal, for example, a Ag@M core-frame nanocrystal is formed. In this structure, the excellent plasmonic and SERS properties of the Ag core are still retained while the deposited M brings in new catalytic capabilities. Alternatively, when the M atoms are conformally deposited on the entire surface, a Ag@M core-shell nanocrystal is created.10 In this case, the M shell can greatly improve the chemical stability of the particle, in addition to the new catalytic properties associated with M. If the shell is kept below 1–2 nm thick, the excellent plasmonic and SERS properties of the Ag core can still be leveraged. Significantly, both SERS and catalytic properties can be integrated in the core-frame and core-shell nanocrystals to offer a unique probe for in situ detection and analysis of catalytic reactions by SERS.
Publication in Nanoscale Article: Xiaojun Sun
September, 2017
We report a facile synthesis of Pt-Ag nanocages with walls thinner than 2 nm by depositing a few atomic layers of Pt as conformal shells on Ag nanocubes and then selectively removing the Ag template via wet etching. We further demonstrate that the as-obtained nanocages with a composition of Pt42Ag58 exhibit enhanced catalytic activity toward the oxygen reduction reaction, with a mass activity of 0.30 A mg−1 and a specific activity of 0.93 mA cm−2, which are 1.6 and 2.5 times, respectively, greater than those of a commercial Pt/C catalyst.
Publication in ACS Nano Article: Jaewan Ahn
December, 2017
We report a facile synthesis of Ag nanocubes with concave side faces and Au-Ag alloy frames, namely Ag@Au-Ag concave nanocrystals, by titrating HAuCl4 solution into an aqueous mixture of Ag nanocubes, ascorbic acid (H2Asc), NaOH, and cetyltrimethylammonium chloride (CTAC) at an initial pH of 11.6 under ambient conditions. Different from all previous studies involving poly(vinylpyrrolidine), the use of CTAC at a sufficiently high concentration plays an essential role in carving away Ag atoms from the side faces through galvanic replacement. Concurrent co-deposition of Au and Ag atoms via chemical reduction at orthogonal sites on the surface of Ag nanocubes leads to the generation of Ag@Au-Ag concave nanocrystals with well-defined and controllable structures.
Graduation 2017: Xiaojun Sun and Junki Kim
December, 2017
Warmest congratulations to Dr. Xiaojun Sun and Junki Kim for the completion of PhD and Master work at Georgia Tech, respectively. Best wishes to their future endeavors!!
New Journey: Dr. Xiaojun Sun
November, 2017
Xiaojun will be joining KLA Tencor after his PhD commencement in December. Congratulations and best wishes to his future endeavors in the bay area!
PhD Thesis Proposal - Jaewan Ahn
February, 2018
Albert successfully defended his thesis proposal: Rational Design and Synthesis of Silver-Based Bimetallic and Trimetallic Nanocrystals for Plasmonics and Catalysis.
Congratulations to Dr. Dong Qin
February, 2018
Dr. Qin has been awarded tenure in the School of Materials Science and Engineering at Georgia Tech, effective August 15, 2018.
Publication in Chemistry of Materials Article: Yun Zhang
February, 2018
We report a simple and general method for the production of Ag-Rh bimetallic nanostructures with a unique integration of plasmonic and catalytic properties exemplified by these two metals, respectively. In a typical process, we titrated a Rh(III) precursor into a polyol suspension of Ag nanocubes held at 110 oC in the presence of ascorbic acid and poly(vinylpyrrolidone). By simply controlling the amount of Rh(III) precursor, we observe the transformation of Ag nanocubes into Ag-Rh core-frame and then Ag-Rh hollow nanocubes with a high porous surface. Upon selective removal of Ag by wet etching, the hollow nanocubes evolve into Ag-Rh and then Rh nanoboxes with highly porous walls. While the Ag-Rh core-frame nanocubes show a unique integration of the plasmonic and catalytic properties characteristic of Ag and Rh, respectively, the Rh nanoboxes show remarkable activity toward the catalytic degradation of environmental pollutants such as organic dyes.
Congratuations to Yiren Wu and Jaewan Ahn: MSE Topping Grant 2018
March, 2018
Based on the scholarly accomplishments, service to the school, as well as advisor’s recommendation, both Yiren and Albert have been selected to receive a one-time topping grant in the amount of $2000 which is in addition to the stipend they currently receive. Funding for the topping grant has been provided by the generous support of the Jewell Family Fellowship Endowment.
Publication in Nanoscale Article: Zhiwei Zhang
April, 2018
We report a facile route to the synthesis of Ag@Au-Pt trimetallic nanocubes in which the Ag, Au, and Pt atoms are exposed at the corners, side faces, and edges, respectively. Our success relies on the use of Ag@Au nanocubes, with Ag2O patches at the corners and Au on the side faces and edges, as seeds for the site-selective deposition of Pt on the edges only in a reaction system containing ascorbic acid (H2Asc) and poly(vinylpyrrolidone). At an initial pH of 3.2, H2Asc can dissolve the Ag2O patches, exposing the Ag atoms at the corners of a nanocube. Upon the injection of H2PtCl6 precursor, the Pt atoms derived from the reduction by both H2Asc and Ag are preferentially deposited on the edges, leading to the formation of Ag@Au-Pt trimetallic nanocubes.
Congratulations to Dr. Dong Qin
April, 2018
Dr. Dong Qin is the recipient of Geoffrey G. Eichholz Faculty Teaching Award in 2018. Since 2012, she always strives her very best to teach all courses with her wholehearted dedication to the success of every student and commitment to fairness. This is the second teaching award from the Tech and she is a receipt of the GT-CETL/BP Junior Faculty Teaching Excellence Award in 2015.
Congratulations to Jaewan (Albert) Ahn
April, 2018
Jaewan (Albert) Ahn received the 3rd place award in the 6th Annual School of Materials Science and Engineering Undergraduate and Graduate Poster Session for his poster titled "Single Atom Catalysis: the Next Generation of Heterogeneous Catalysis" competing under nanomaterials category.
Congratulations to Zheyu (Jerrry) Luo
April, 2018
Zheyu (Jerry) Luo received the 1st place award in the 6th Annual School of Materials Science and Engineering Undergraduate and Graduate Poster Session for his poster titled "Transformation of Silver Nanocubes into Bimetallic Nanocrystals with Desired Optical and Catalytic Properties " competing under nanomaterials category.
Congratulations to Shi (Shirley) Shi
April, 2018
Shi (Shirley) Shi received the 1st place award in the 6th Annual School of Materials Science and Engineering Undergraduate and Graduate Poster Session for her poster titled "Bringing Copolymers to the Synthesis of Metal Nanoparticles: Opportunities and Challenges" competing under first year graduate student category.
Congratulations to Dr. Dong Qin: 2018-2020 Provost Teaching and Learning Fellow