Ionic Liquid-Based Polymer Electrolytes via Surfactant-Assisted Polymerization at the Plasma–Liquid Interface

Tran, Quoc Chinh,Bui, Van-Tien,Dao, Van-Duong,Lee, Joong-Kee,Choi, Ho-Suk American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.25

<P>We first report an innovative method, which we refer to as interfacial liquid plasma polymerization, to chemically cross-link ionic liquids (ILs). By this method, a series of all-solid state, free-standing polymer electrolytes is successfully fabricated where ILs are used as building blocks and ethylene oxide-based surfactants are employed as an assisted-cross-linking agent. The thickness of the films is controlled by the plasma exposure time or the ratio of surfactant to ILs. The chemical structure and properties of the polymer electrolyte are characterized by scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS). Importantly, the underlying polymerization mechanism of the cross-linked IL-based polymer electrolyte is studied to show that fluoroborate or halide anions of ILs together with the aid of a small amount of surfactants having ethylene oxide groups are necessary to form cross-linked network structures of the polymer electrolyte. The ionic conductivity of the obtained polymer electrolyte is 2.28 X 10(-3) S.cm(-1), which is a relatively high value for solid polymer electrolytes synthesized at room temperature. This study can serve as a cornerstone for developing all-solid state polymer electrolytes with promising properties for next-generation electrochemical devices.</P>

Pt-based alloy/carbon black nanohybrid covered with ionic liquid supramolecules as an efficient catalyst for oxygen reduction reactions

Tran, Quoc Chinh,Dao, Van-Duong,Kim, Hyun You,Jung, Kwang-Deog,Choi, Ho-Suk Elsevier 2017 Applied catalysis. B, Environmental Vol.204 No.-

<P><B>Abstract</B></P> <P>A facile strategy is reported for synthesizing ionic liquid supramolecules (ILSMs) as well as Pt-based alloys on the carbon black surface in a room temperature ionic liquid (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide) under one atmospheric pressure plasma. The bimetallic PtNi-nanoparticles (NPs) with a size of 2.5–3nm are stably and uniformly hybridized on the surface of the carbon black, which is covered with a layer of ILSMs. The formation of the developed catalyst is examined using TEM, HAADF-STEM, XRD, TEM-EDS, and TGA measurements. The obtained catalyst exhibits high oxygen reduction reaction (ORR) activity, which is better than those of commercial Pt/C catalysts and Pt/C catalysts prepared without using ionic liquids. This strategy has been extended to fabricate trimetallic PtNiRu-NPs/C nanohybrids with further enhanced activities of up to 2.26mAcm<SUP>−2</SUP> and 1.31Amg<SUB>Pt</SUB> <SUP>−1</SUP> at 0.9V versus RHE. The trimetallic PtNiRu-NPs/C catalyst is also more stable than the commercial product under ORR conditions due to the chemical binding of the alloys with the carbon black and the physical stabilization of the nanohybrid materials through the conductive protecting layer of the ILSMs. The results prove that the developed catalysts push the ORR toward completion and can be a promising candidate for numerous electrocatalytic applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pt-based alloy/carbon black nanohybrids are synthesized in ionic liquid through using plasma. </LI> <LI> The nanohybrids are covered with a layer of ionic liquid supramolecules (ILSMs). </LI> <LI> An increase in the activity of the nanohybrid catalysts results from the ILSMs. </LI> <LI> The activity of the PtNiRu-IL/C catalyst is 10.8 times higher than those of c-Pt/C. </LI> <LI> The catalysts developed exhibit long-term stability as well as excellent activity for ORR. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P> <P>This study proposes a strategy to continuously, uniformly, stably and simultaneously synthesize Pt-based alloy/carbon black nanohybrid covered with ionic liquid supramolecules through wet plasma reduction. The developed Pt-based alloy/carbon black nanohybrid covered with ionic liquid supramolecules outperformed the superior ORR activity compared with the commercial Pt/C.</P>

Robust graphene-wrapped PtNi nanosponge for enhanced oxygen reduction reaction performance

Tran, Quoc Chinh,An, Hyesung,Ha, Hyunwoo,Nguyen, Van Toan,Quang, Nguyen Duc,Kim, Hyun You,Choi, Ho-Suk The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.18

<P>We synthesize a graphene-wrapped 3D-PtNi nanosponge (G-PtNi NS) using formic acid as a reducing agent and carbon dots as a structure-directing agent at room temperature. Reduced Ni and Pt atoms initiate the exfoliation of carbon dots into graphene dots, which eventually encapsulate the PtNi nanocrystals. The strong Pt-carbon interaction propels the formation of the G-PtNi NS with large specific surface area and good long-term stability. The G-PtNi NS shows high reactivity for an oxygen reduction reaction (ORR). The ORR activity is maintained even after 3000 cycles. We confirm that the graphene layers physically stabilize the PtNi NS and chemically adjust the oxygen affinity of the PtNi NS, which both positively contribute to the ORR performance.</P>

Polyhedral gold nanocrystals/polyelectrolyte composite film: One-pot synthesis via interfacial liquid plasma polymerization

Tran, Quoc Chinh,Ha, Hyunwoo,Lee, Sumin,Bae, Kyung-Ho,Kim, Ohsub,Cho, Yong Seok,Yoon, Ilsun,Kim, Hyun You,Choi, Ho-Suk Elsevier 2017 Composites science and technology Vol.153 No.-

<P><B>Abstract</B></P> <P>In contrast with the conventional <I>in situ</I> and <I>ex situ</I> methods for the preparation of polymer-based nanocomposites in which the polymer matrix (for both methods) and metal nanoparticles (for the <I>ex situ</I> method only) are prepared separately prior to being combined to form the composite, polyhedral gold nanocrystal/polymer composite film was successfully synthesized through combining the <I>in situ</I> formation of gold nanocrystals (AuNCs) and simultaneous polymerization of the polyelectrolytes from ionic liquids and surfactants under atmospheric pressure plasma. The composite film contained a large number of well-shaped polyhedral AuNCs. The AuNCs are stereoscopically distributed in the polyelectrolyte matrix without agglomeration. The size of the AuNCs prepared in a 3 mm deep reactor decreased along the cross section of the composite film from top to bottom, while they were uniform in size when they were prepared in a 5 mm deep reactor. In the presence of the Au precursors, the polymer film thickness increases to 7.03 μm, which is two-fold thicker than that of the polymer film prepared without adding Au precursors. Through the density functional theory (DFT) calculations, the critical role of Triton X100 was clearly demonstrated in the formation of the well-shaped AuNCs. The composite film exhibited the reduction of ∼66% in Young's modulus and the reduction of ∼44% in hardness compared to the neat polymer film. Finally, an appropriate mechanism is proposed for the formation of the polyhedral AuNC/polyelectrolyte composite film.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

대면적 대기압 플라즈마-용액 시스템을 이용한 폴리프로필렌 표면 처리

트란꺽시 ( Chinh Quoc Tran ),최호석 ( Ho Suk Choi ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.3

We investigated the possibility of introducing functional groups without damaging surface polymeric chains through the treatment of a polypropylene(PP) film immersed in liquid phase using an atmospheric pressure plasma with large area. The ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate: [BMIM]+[BF4]- was successfully applied for generating stable plasmas in the plasma-solution system. We successfully treated the film surface using the plasma-solution system and confirmed various oxygen-containing functional groups formed on the surface of film. The surface free energy of PP film was increased with increasing plasma treatment time and power. It also showed a maximum value at the PP sample treated in the ionic liquid solution of 1.5 M. ATR-FTIR analyses revealed the increase of various carbonyl groups(l,726 cm-1, 1,643 cm-1) and OH groups(3,l00~3,500 cm-1) after plasma treatment of PP film, and XPS also supported the ATR-FTIR result.

N-doped Cdot/PtPd nanonetwork hybrid materials as highly efficient electrocatalysts for methanol oxidation and formic acid oxidation reactions

Nguyen, Van-Toan,Tran, Quoc Chinh,Quang, Nguyen Duc,Nguyen, Ngoc-Anh,Bui, Van-Tien,Dao, Van-Duong,Choi, Ho-Suk Elsevier 2018 Journal of alloys and compounds Vol.766 No.-

<P><B>Abstract</B></P> <P>The improvement of the catalytic performance for methanol and formic acid oxidation reactions remains a key issue for the development of a new generation of direct methanol and formic acid fuel cells. This study reports a simple approach, using selective chemical etching for the synthesis of unique nitrogen-doped carbon dot/Pt<SUB>84</SUB>Pd<SUB>16</SUB> (N-Cdot/Pt<SUB>84</SUB>Pd<SUB>16</SUB>) nano-network structure at room temperature with excellent electrocatalytic properties. The obtained nano-network hybrid material exhibits significant enhancement of the electrocatalytic activity for the electro-oxidation reaction of both methanol and formic acid with current densities of 999.0 and 1919.5 mA/mg<SUB>metal</SUB>, respectively, compared with the commercial ones of 751.32 and 806.02 mA/mg<SUB>metal</SUB>, respectively. Furthermore, the N-Cdot/Pt<SUB>84</SUB>Pd<SUB>16</SUB> nano-network hybrid materials exhibit excellent stability and hydrophilic dispersibility at room temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N-Cdot/PtPd nanonetwork hybrid material is synthesized at room temperature. </LI> <LI> A simple coreduction and a selective chemical etching are applied to the synthesis. </LI> <LI> It generates a nano-network structure with excellent electrocatalytic properties. </LI> <LI> N-Cdot functions as a uniform interconnection between the nanohybrid materials. </LI> <LI> The hybrid exhibits significant enhancement of the activity for both MOR and FAOR. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Synthesis of Poly(Ionic Liquids) via Interfacial Liquid Plasma Polymerization: Effect of Ethylene Oxide Groups

김오섭,배경호,최호석,Quoc-Chinh Tran,Van-Tien Bui 한국고분자학회 2018 한국고분자학회 학술대회 연구논문 초록집 Vol.43 No.1

Evaluation of Pt-based alloy/graphene nanohybrid electrocatalysts for triiodide reduction in photovoltaics

Dao, Van-Duong,Larina, Liudmila L.,Tran, Quoc Chinh,Bui, Van-Tien,Nguyen, Van-Toan,Pham, Thanh-Dong,Mohamed, Ibrahim M.A.,Barakat, Nasser A.M.,Huy, Bui The,Choi, Ho-Suk Elsevier 2017 Carbon Vol.116 No.-

<P>This work focuses on systematic studies of dissolution engineering for Pt0.9M0.1/graphene(M = Au, Co, Cu, Fe, Mo, Ni, Pd, Ru, and Sn) counter electrodes (CEs). The developed nanohybrid materials exhibit higher catalytic activity and electrical conductivity compared with those of Pt/graphene CEs. The results also indicate the improved stability of the developed CEs in iodide electrolyte. Furthermore, the trend in the variation of the reactivity of the PtM alloys agrees well with the concept of density functional theory (one-electron description). An enhancement in the catalytic activity of the developed nanohybrids results from the electronic effect that originates from an upward shift of the platinum d-band to the Fermi energy level upon alloying. Thus, the Pt(0.9)M(0.1)graphene nanohybrids are cost-effective alternative CE materials to the expensive Pt. The obtained results provide a foundation for enhancing the catalytic activities of CEs for dye-sensitized solar cells (DSCs). The implementation of the Pt0.9M0.1/graphene nanohybrids offers significant potential for increasing the efficiency of DSCs. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Graphene dot armored PtMo nanosponge as a highly efficient and stable electrocatalyst for hydrogen evolution reactions in both acidic and alkaline media

Nguyen, Van-Toan,Nguyen, Ngoc-Anh,Ali, Yousuf,Tran, Quoc Chinh,Choi, Ho-Suk Elsevier 2019 Carbon Vol.146 No.-

<P><B>Abstract</B></P> <P>A new type of three-dimensional PtMo nanosponge wrapped with graphene dots (abbreviated as 3D Pt<SUB>x</SUB>Mo<SUB>1-x</SUB>@graphene) has been developed for catalyzing the hydrogen evolution reaction (HER). The graphene-dot wrapping takes place via the exfoliation of carbon dots during the co-reduction of Pt/Mo precursors and carbon dots at a low temperature in an aqueous solution. The synergistic effects of inner metallic alloy networks and outer graphene dots in the 3D Pt<SUB>x</SUB>Mo<SUB>1-x</SUB>@graphene are responsible for the outstanding HER performance and superb durability in both acidic and alkaline electrolytes. The 3D Pt<SUB>x</SUB>Mo<SUB>1-x</SUB>@graphene shows a low Tafel slope of 32 mV/dec and 51 mV/dec together with a low overpotential of 32 mV and 97 mV at a current density of −10 mA cm<SUP>−2</SUP> in acidic and alkaline media, respectively. The catalyst also shows superb stability, as confirmed by a large amount of repeated potential cycling exceeding 5000 cycles in acidic solution and long-term durability of over 50,000 seconds in an alkaline solution. This work provides a new feasible mean of synthesizing graphene-dot-wrapped Pt-based nanostructures with highly efficient catalytic activity and superb stability for HER without the need for surfactants or stabilizers.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>