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Journal Article
Chen, J-C, Chen P-Y, Chen H-Y, Chen K-H.  2018.  Analysis and characterization of an atropisomeric ionomer containing quaternary ammonium groups. Polymer. 141:143-153. AbstractWebsite

Polyethersulfone ionomers containing quaternary ammoniums were prepared for the applications on alkaline anion exchange membrane (AAEM) fuel cells. The ionomers were synthesized from 2,2′-dimethyl-4,4′-biphenyldiol and bis(4-chlorophenyl) sulfone via nucleophilic substitution followed by bromination, quaternization and anion exchange reaction. The biphenyl structure in polymer main chain exhibited atropisomerism after bromination, leading to the anisochronous signals of geminal protons on bromomethyl groups in 1H NMR spectra. Model compounds were synthesized to confirm the atropisomerism by EI mass and 1H NMR spectra. The resonance peaks from five possible repeating units of brominated polyethersulfones in the 1H NMR spectra were identified and discussed in detail. The rotational barriers of biphenyl structures containing brominated methyl groups at 2 and 2′ positions were calculated by density functional theory. The properties of these polyethersulfone anion exchange membranes (AEMs) were characterized. Their IECs ranged from 0.81 to 1.75 mequiv/g. The corresponding water uptakes and dimensional changes were in the ranges of 19–42% and 12–38%, respectively. The tensile strength of an AEM (1.75MQAPES-OH) with an IEC of 1.75 mequiv/g remained 17 MPa even though the water uptake was 42%. The hydroxide conductivity of 1.75MQAPES-OH could reach 51.4 mS/cm at 98%RH and 80 °C. After alkaline stability test for 168 h, the AEMs degraded slightly in terms of their IECs and hydroxide conductivity.

Billo, T, Fu F-Y, Raghunath P, Shown I, Chen W-F, Lien H-T, Shen T-H, Lee J-F, Chan T-S, Huang K-Y, Wu C-I, Lin MC, Hwang J-S, Lee C-H, Chen L-C, Chen K-H.  2018.  Ni-Nanocluster Modified Black TiO2 with Dual Active Sites for Selective Photocatalytic CO2 Reduction. Small. 14:1702928–n/a., Number 2 AbstractWebsite

One of the key challenges in artificial photosynthesis is to design a photocatalyst that can bind and activate the CO2 molecule with the smallest possible activation energy and produce selective hydrocarbon products. In this contribution, a combined experimental and computational study on Ni-nanocluster loaded black TiO2 (Ni/TiO2[Vo]) with built-in dual active sites for selective photocatalytic CO2 conversion is reported. The findings reveal that the synergistic effects of deliberately induced Ni nanoclusters and oxygen vacancies provide (1) energetically stable CO2 binding sites with the lowest activation energy (0.08 eV), (2) highly reactive sites, (3) a fast electron transfer pathway, and (4) enhanced light harvesting by lowering the bandgap. The Ni/TiO2[Vo] photocatalyst has demonstrated highly selective and enhanced photocatalytic activity of more than 18 times higher solar fuel production than the commercial TiO2 (P-25). An insight into the mechanisms of interfacial charge transfer and product formation is explored.

Chiu, J-M, Chou T-chin, Wong DP, Lin Y-R, Shen C-A, Hy S, Hwang B-J, Tai Y, Wu H-L, Chen L-C, Chen K-H.  2018.  A synergistic “cascade” effect in copper zinc tin sulfide nanowalls for highly stable and efficient lithium ion storage. Nano Energy. 44:438-446. AbstractWebsite
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Fang, S-L, Chou T-chin, Samireddi S, Chen K-H, Chen L-C, Chen W-F.  2017.  Enhanced hydrogen evolution reaction on hybrids of cobalt phosphide and molybdenum phosphide, 2017/03/01. Royal Society open science. 4(3):161016161016-161016.: The Royal Society Publishing AbstractWebsite

Production of hydrogen from water electrolysis has stimulated the search of sustainable electrocatalysts as possible alternatives. Recently, cobalt phosphide (CoP) and molybdenum phosphide (MoP) received great attention owing to their superior catalytic activity and stability towards the hydrogen evolution reaction (HER) which rivals platinum catalysts. In this study, we synthesize and study a series of catalysts based on hybrids of CoP and MoP with different Co/Mo ratio. The HER activity shows a volcano shape and reaches a maximum for Co/Mo = 1. Tafel analysis indicates a change in the dominating step of Volmer-Hyrovský mechanism. Interestingly, X-ray diffraction patterns confirmed a major ternary interstitial hexagonal CoMoP(2) crystal phase is formed which enhances the electrochemical activity.

Ebrahimi, M, Samadi M, Yousefzadeh S, Soltani M, Rahimi A, Chou T-chin, Chen L-C, Chen K-H, Moshfegh AZ.  2017.  Improved Solar-Driven Photocatalytic Activity of Hybrid Graphene Quantum Dots/ZnO Nanowires: A Direct Z-Scheme Mechanism, 2017. ACS Sustainable Chemistry & EngineeringACS Sustainable Chemistry & Engineering. 5(1):367-375.: American Chemical Society AbstractWebsite
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Lee, S-W, Chen J-C, Wu J-A, Chen K-H.  2017.  Synthesis and Properties of Poly(ether sulfone)s with Clustered Sulfonic Groups for PEMFC Applications under Various Relative Humidity, 2017. ACS Applied Materials & InterfacesACS Applied Materials & Interfaces. 9(11):9805-9814.: American Chemical Society AbstractWebsite
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Wei-ChaoChen, Tunuguntla V, Min-HsuehChiu, Lian-JiunLi, Shown I, Lee C-H, Hwang J-S, Chen L-C, Chen K-H.  2017.  Co-solvent effect on microwave-assisted Cu2ZnSnS4 nanoparticles synthesis for thin film solar cell. Solar Energy Materials and Solar Cells. 161:416-423.
Ciao-WeiYang, Chin-ChangChen, Chen K-H, SoofinCheng.  2017.  Effect of pore-directing agents in SBA-15 nanoparticles on the performance of Nafion®/SBA-15n composite membranes for DMFC. Journal of Membrane Science. 526:106-117.
Ramakrishnan, A, Raman S, Chen L-C, Chen K-H.  2017.  Enhancement in Thermoelectric Properties of TiS2 by Sn Addition. Journal of Electronic Materials. :1–8.
Chiu, J-M, Chen E-M, Lee C-P, Shown I, Tunuguntla V, Chou J-S, Chen L-C, Chen K-H, Tai Y.  2017.  Geogrid-Inspired Nanostructure to Reinforce a CuxZnySnzS Nanowall Electrode for High-Stability Electrochemical Energy Conversion Devices. Advanced Energy Materials. 7(12):1602210.
Pathak, A, Chiou GR, Gade NR, Usman M, Mendiratta S, Luo T-T, Tseng TW, Chen J-W, Chen F-R, Chen K-H, Chen L-C, Lu K-L.  2017.  High-κ Samarium-Based Metal–Organic Framework for Gate Dielectric Applications. ACS Appl. Mater. Interfaces. 9(26):21872–21878.
Samireddi, S, Shown I, Shen T-H, Huang H-C, Wong K-T, Chen L-C, Chen K-H.  2017.  Hybrid bimetallic-N4 electrocatalyst derived from a pyrolyzed ferrocene–Co-corrole complex for oxygen reduction reaction. Journal of Materials Chemistry A. 5:9279-9286.
Qorbani, M, Chou T-chin, Lee Y-H, Samireddi S, Naseri N, Ganguly A, Esfandiar A, Wang C-H, Chen L-C, Chen K-H, Moshfegh AZ.  2017.  Multi-porous Co3O4 nanoflakes @ sponge-like few-layer partially reduced graphene oxide hybrids: towards highly stable asymmetric supercapacitors. Journal of Materials Chemistry A. 5:12569-12577.
Lin, CH, Chen RS, Lin YK, Wang SB, Chen LC, Chen KH, Wen MC, Chou MMC, Chang L.  2017.  Photoconduction properties and anomalous power-dependent quantum efficiency in non-polar ZnO epitaxial films grown by chemical vapor deposition. APPLIED PHYSICS LETTERS . 110:052101.
Huang, H-C, Chang S-T, Hsu H-C, Du H-Y, Wang C-H, Chen L-C, Chen K-H.  2017.  Pyrolysis of Iron–Vitamin B9 As a Potential Nonprecious Metal Electrocatalyst for Oxygen Reduction Reaction. Search Results ACS Sustainable Chemistry & Engineering. 5 (4):2897–2905.
Lee, S-W, Chen J-C, Wu J-A, Chen K-H.  2017.  Synthesis and Properties of Poly(ether sulfone)s with Clustered Sulfonic Groups for PEMFC Applications under Various Relative Humidity. ACS Appl. Mater. Interfaces. 9(11):9805–9814.
Lee, C-P, Chen W-F, Billo T, Lin Y-G, Fu F-Y, Samireddi S, Lee C-H, Hwang J-S, Chen K-H, Chen L-C.  2016.  Beaded stream-like CoSe2 nanoneedle array for efficient hydrogen evolution electrocatalysis, 2016. Journal of Materials Chemistry A. 4(12):4553-4561.: The Royal Society of Chemistry AbstractWebsite

The development of earth-abundant and efficient electrocatalysts for the hydrogen evolution reaction (HER) is one of the keys to success for future green energy systems using hydrogen fuel. Nanostructuring of electrocatalysts is a promising way to enhance their electrocatalytic performance in the HER. In this study, pure pyrite-type beaded stream-like cobalt diselenide (CoSe2) nanoneedles are directly formed on flexible titanium foils through treating a cobalt oxide (Co3O4) nanoneedle array template with selenium vapor. The beaded stream-like CoSe2 nanoneedle electrode can drive the HER at a current density of 20 mA cm−2 with a small overpotential of 125 mV. Moreover, the beaded stream-like CoSe2 nanoneedle electrode remains stable in an acidic electrolyte for 3000 cycles and continuously splits water over a period of 18 hours. The enhanced electrochemical activity is facilitated by the unique three-dimensional hierarchical structure, the highly accessible surface active sites, the improved charge transfer kinetics and the highly attractive force between water and the surface of the nanoneedles that exceeds the surface tension of water.

Tran Nguyen, NH, Nguyen TH, Liu Y-ren, Aminzare M, Pham ATT, Cho S, Wong DP, Chen K-H, Seetawan T, Pham NK, Ta HKT, Tran VC, Phan TB.  2016.  Thermoelectric Properties of Indium and Gallium Dually Doped ZnO Thin Films, 2016. ACS Applied Materials & InterfacesACS Applied Materials & Interfaces. 8(49):33916-33923.: American Chemical Society AbstractWebsite
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Lin, Y-K, Chen R-S, Chou T-chin, Lee Y-H, Chen Y-F, Chen K-H, Chen L-C.  2016.  Thickness-Dependent Binding Energy Shift in Few-Layer MoS2 Grown by Chemical Vapor Deposition, 2016. ACS Applied Materials & InterfacesACS Applied Materials & Interfaces. 8(34):22637-22646.: American Chemical Society AbstractWebsite
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Lee, CP, Chen* WF, Billo T, Lin YG, Fu FY, Samireddi S, Lee CH, Hwang JS, Chen* LC, Chen* KH.  2016.  Beaded-stream-like CoSe2 nanoneedles array for efficient hydrogen evolution electrocatalysis. J. Mater. Chem. A . 4 :4553-4561.
Wei-ChaoChen, Cheng-YingChen, Tunuguntla V, HungLu S, ChaochinSu, Lee C-H, Chen K-H, Chen L-C.  2016.  Enhanced solar cell performance of Cu2ZnSn(S,Se)4 thin films through structural control by using multi-metallic stacked nanolayers and fast ramping process for sulfo-selenization. Nano Energy. 30:762-770.
Wong, DP, Huang CY, Chien WL, Chang CE, Ganguly A, Lyu LM, Hwang JS, Chen LC, Chen KH.  2016.  Enhanced thermoelectric performance in percolated bismuth sulfide composite. RSC Advances . 6:98952.
Chen, WC, Tunuguntla V, Li HW, Chen CY, Li SS, Hwang JS, Lee CH, Chen LC, Chen KH.  2016.  Fabrication of Cu2ZnSnSe4 solar cells through multi-step selenization of layered metallic precursor film. Thin Solid Films .
Chen, IN, Chong CW, Lyu LM, Wong DP, Chien WL, Anbu A, Chen YF, Chen LC, Chen KH.  2016.  Improving the thermoelectric performance of metastable rock-salt GeTe-rich Ge-Sb-Te thin films through tuning of grain orientation and vacancies. Physica Status Solidi A . :1-8.
Wang, B-Y, Wang HT, Chen L-Y, Hsueh HC, Chiou JW, Wang W-H, Wang PH, Chen K-H, Chen Y-C, Chen L-C, Chen C-H, Pong WF, Wang J, Guo J-H.  2016.  Nonlinear opening of the band gap of BN-co-doped graphene. Carbon.