Browsing by Author "Kuo, Chun-Hong"

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Au-BINOL Hybrid Nanocatalysts: Insights into the Structure-Based Enhancement of Catalytic and Photocatalytic Performance
(2019-04-10)
Patolla, Shashank Reddy
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Kao, Chen-Rui
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Chen, Guan-Wei
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Huang, Yu-Cheng
;
Chuang, Yu-Chun
Advances in new systems of organic-inorganic hybrid nanocomposites are less prevalent, owing to a lack of facile strategies for precise control of their structures, compositions, and, hence, their properties. In this work, Au-BINOL hybrid nanocomposites with eccentric and concentric nanostructures were produced. The hybrid nanocomposites containing two distinct moieties of inorganic Au nanocrystals and organic BINOL nanospheres were applied to the catalytic hydrogenation of 4-nitrophenol with NaBH4 in the aqueous phase with and without the illumination of visible light. Here, we demonstrate that the existence of Au-BINOL interfaces offers benefits to their performance. The eccentric nanostructures made with CTAC show the superior activity from large Au-BINOL interfaces formed between the BINOL nano spheres and the faces of Au nanoplates. They further exhibit a high Au localized surface plasmon resonance (LSPR)-enhancement effect on the photoreduction of 4-nitrophenol, which is attributed to the strong LSPR absorption of exposed Au nanocrystals unaffected by the coverage of BINOL shells.
Electronic structures associated with enhanced photocatalytic activity in nanogap-engineered g-C3N4/Ag@SiO2 hybrid nanostructures
(2020-06-01)
Huang, Yu-Cheng
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Arul, K. Thanigai
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Chen, Chi-Liang
;
Chen, Jeng-Lung
;
Chen, Jie
Graphitic carbon nitride (g-C3N4) has attracted considerable attention with regard to its use in photocatalytic solar hydrogen production by the splitting of water. High charge carrier recombination critically limits the photocatalytic activity of g-C3N4. Plasmonic metal nanoparticles that can generate localized surface plasmon resonance (LSPR) have been suggested to enhance the harvesting of visible light and to improve water splitting efficiency. However, direct contact between metal nanoparticles and g-C3N4 reduces the hydrogen generation efficiency owing to energy loss by Forster resonance energy transfer (FRET), which competes with plasmon resonance energy transfer (PRET). Decorating g-C3N4 with Ag@SiO2 core-shell plasmonic nanoparticles increases its photocatalytic ability. Tuning the size of the SiO2 nanogap can optimize the photocatalytic performance of g-C3N4/Ag@SiO2, which involves a trade-off between PRET and FRET. X-ray absorption spectroscopy (XAS) is utilized to investigate the electronic structure of g-C3N4 and its modulation with Ag@SiO2. In situ XAS reveals the dynamics of the charge carriers under solar illumination. Analytic results suggest charge redistribution, shifting of the conduction band, modification of the unoccupied states, and consequent improvement in photocatalytic activity by solar illumination. This work sheds light on the effect of LSPR on this photocatalyst with reference to its electronic structure.
Interface-Controlled Synthesis of Au-BINOL Hybrid Nanostructures and Mechanism Study
(2018-11-13)
Patlolla, Shashank Reddy
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Kao, Chen-Rui
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Yeh, Ai-Hsuan
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Lin, Hung-Min
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Chuang, Yu-Chun
The combined functionality of components in organic inorganic hybrid nanomaterials render them efficient nanoreactors. However, the development in this field is limited due to a lack of synthetic avenues and systematic control of the growth kinetics of hybrid structures. In this work, we take advantage of an ionic switch for regio-control of Au-BINOL(1,1'-Bi-2-naphthol) hybrid nanostructures. Aromatic BINOL molecules assemble into nanospheres, concomitant with the growth of the Au nanocrystals. The morphological evolution of Au nanocrystals is solely controlled by the presence of halides in the synthetic system. Here we show that quaternary ammonium surfactants (CTAB or CTAC), not only bridging Au and BINOL, but also contributing to the formation of concentric or eccentric structures when their concentrations are tuned to the range of 10(-5) to 10(-3) M. This facile strategy offers the potential advantage of scalable production, with diverse functional organic inorganic hybrid nanocomposites being produced based on the specific archetype of Au-BINOL hybrid nano composites.
NiCo2O4/graphene quantum dots (GQDs) for use in e fficient electrochemical energy devices: An electrochemical and X-ray absorption spectroscopic investigation
(2020-05-15)
Chang, Han-Wei
;
Fu, Ji-Xuan
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Huang, Yu-Cheng
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Lu, Ying-Rui
;
Kuo, Chun-Hong
NiCo2O4/graphene quantum dots (GQDs) were synthesized by the incorporation of GQDs into NiCo2O4 as electrode materials for use in electrochemical energy devices. The electronic structure and the electrochemical performance of NiCo2O4/GQDs were investigated by X-ray absorption spectroscopy (XAS) and electrochemical measurements. The rich redox active sites were revealed on the NiCo2O4/GQDs, which were formed by the strong CeOeNi/Co interaction between NiCo2O4 and GQDs. The synergetic double-layer capacitive and pseudocapacitive properties were suggested to provide favorable electrochemical characteristics. In/ex situ XAS elucidates local electronic and chemical environments and provides insights into the energy storage/conversion mechanisms. Analytical results demonstrate that the NiCo2O4/GQDs have strong oxygen-carbon bridges and have more Ni active sites than does NiCo2O4, favoring metal-to-ligand charge transfer at the interface between NiCo2O4 and GQDs, critically influencing electrochemical performance. This work contributes importantly to the field by elucidating an energy storage/conversion mechanism for electrochemical energy devices.
PLASMONIC-ENHANCED POLYMER PHOTOVOLTAIC DEVICES INCORPORATING AU NANOPARTICLES
(2010)
Wu, Jyh-Lih
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Lee, Chia-Lin
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Chen, Fang-Chung
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Kuo, Chun-Hong
;
Huang, Michael H.
We have improved the device performance of polymer photovoltaic devices (OPVs) by blending Au nanoparticles (NPs) into the anodic buffer layer. The unique optical properties of localized surface plasmon resonance (LSPR), triggered by Au NPs, was beneficial for improving the photocurrent of OPVs. The excitation of LSPR increased not only the exciton generation rate but also the exciton dissociation probability. As a result, the power conversion efficiency of OPVs has been significantly enhanced from 3.57 to 4.24%.
Plasmonic-enhanced polymer photovoltaic devices incorporating solution-processable metal nanoparticles
(2009-07-06)
Chen, Fang-Chung
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Wu, Jyh-Lih
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Lee, Chia-Ling
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Hong, Yi
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Kuo, Chun-Hong
We have explored the effect of gold nanoparticle (Au NP)-induced surface plasmons on the performance of organic photovoltaic devices (OPVs). The power conversion efficiency of these OPVs was improved after blending the Au NPs into the anodic buffer layer. The addition of Au NPs increased the rate of exciton generation and the probability of exciton dissociation, thereby enhancing the short-circuit current density and the fill factor. We attribute the improvement in device performance to the local enhancement in the electromagnetic field originating from the excitation of the localized surface plasmon resonance. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3174914]
Selective electrocatalytic N2 reduction to ammonia by bimetallic nanocrystal
(2019-08-25)
Talukdar, Biva
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Kuo, Chun-Hong
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應用化學系
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Department of Applied Chemistry
Solar H2 production: CuGa1-xFexO2-carbon nitride as a novel p-n heterojunction for photocatalytic water-splitting
(2019-08-25)
Martinez, Benjamin
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Kuo, Chun-Hong
;
應用化學系
;
Department of Applied Chemistry
Surface Plasmonic Effects of Metallic Nanoparticles on the Performance of Polymer Bulk Heterojunction Solar Cells
(2011-02-01)
Wu, Jyh-Lih
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Chen, Fang-Chung
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Hsiao, Yu-Sheng
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Chien, Fan-Ching
;
Chen, Peilin
We have systematically explored how plasmonic effects influence the characteristics of polymer photovoltaic devices (OPVs) incorporating a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM). We blended gold nanoparticles (Au NPs) into the anodic buffer layer to trigger localized surface plasmon resonance (LSPR), which enhanced the performance of the OPVs without dramatically sacrificing their electrical properties. Steady state photoluminescence (PL) measurements revealed a significant increase in fluorescence intensity, which we attribute to the increased light absorption in P3HT Induced by the LSPR. As a result, the rate of generation of excitons was enhanced significantly. Furthermore, dynamic PL measurements revealed that the LSPR notably reduced the lifetime of photogenerated excitons In the active blend, suggesting that interplay between the surface plasmons and excitons facilitated the charge transfer process. This phenomenon reduced the recombination level of geminate excitons and, thereby, Increased the probability of exciton dissociation. Accordingly, both the photocurrents and fill factors of the OPV devices were enhanced significantly. The primary origin of this improved performance was local enhancement of the electromagnetic field surrounding the Au NPs. The power conversion efficiency of the OPV device incorporating the Au NPs improved to 4.24% from a value of 3.57% for the device fabricated without Au NPs.