化學系
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國立臺灣師範大學化學系座落於公館校區理學院大樓。本系成立於民國五十一年，最初僅設大學部。之後於民國六十三年、七十八年陸續成立化學研究所碩士班和博士班。本系教育目標旨在培養化學專業人才與中等學校自然及化學專業師資，授課著重理論及應用性。本系所現有師資為專任教授25人，另外尚有與中央研究院合聘教授3位，在分析、有機、無機及物理化學四個學門的基礎上發展跨領域之教學研究合作計畫。此外，本系另有助教13位，職技員工1位，協助處理一般學生實驗及行政事務。學生方面，大學部現實際共322人，碩士班現實際就學研究生共174人，博士班現實際就學共55人。
本系一向秉持著教學與研究並重，近年來為配合許多研究計畫的需求，研究設備亦不斷的更新。本系所的研究計畫大部分來自國科會的經費補助。此外，本系提供研究生獎助學金，研究生可支領助教獎學金（TA）、研究獎學金（RA）和部分的個別教授所提供的博士班學生獎學金（fellowships）。成績優良的大學部學生也可以申請獎學金。
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Item Simple Replacement Reaction for the Preparation of Ternary Fe1?xPtRux Nanocrystals with Superior Catalytic Activity in Methanol Oxidation Reaction.(American Chemical Society, 2012-06-20) D.-Y. Wang; H.-L. Chou; Y.-C. Lin; F.-J. Lai; C.-H. Chen; J.-F. Lee; B.-J. Hwang; Chia-Chun ChenThe finding of new metal alloyed nanocrystals (NCs) with high catalytic activity and low cost to replace PtRu NCs is a critical step toward the commercialization of fuel cells. In this work, a simple cation replacement reaction was utilized to synthesize a new type of ternary Fe1–xPtRux NCs from binary FePt NCs. The detailed structural transformation from binary FePt NCs to ternary Fe1–xPtRux NCs was analyzed by X-ray absorption spectroscopy (XAS). Ternary Fe35Pt40Ru25, Fe31Pt40Ru29, and Fe17Pt40Ru43 NCs exhibit superior catalytic ability to withstand CO poisoning in methanol oxidation reaction (MOR) than do binary NCs (FePt and J-M PtRu). Also, the Fe31Pt40Ru29 NCs had the highest alloying extent and the lowest onset potential among the ternary NCs. Furthermore, the origin for the superior CO resistance of ternary Fe1–xPtRux NCs was investigated by determining the adsorption energy of CO on the NCs’ surfaces and the charge transfer from Fe/Ru to Pt using a simulation based on density functional theory. The simulation results suggested that by introducing a new metal into binary PtRu/PtFe NCs, the anti-CO poisoning ability of ternary Fe1–xPtRux NCs was greatly enhanced because the bonding of CO–Pt on the NCs’ surface was weakened. Overall, our experimental and simulation results have indicated a simple route for the discovery of new metal alloyed catalysts with superior anti-CO poisoning ability and low usage of Pt and Ru for fuel cell applications.Item Silver-Nanoparticle-Conjugated Polypeptide Brushes for Surface-Enhanced Raman Scattering(American Chemical Society, 2009-08-06) D.-Y. Wang; T.-S Teng; Y.-C. Wu; Y.-C. Lee; K.-H. Chen; C.-H. Chen; Y.-C. Chang; Chia-Chun ChenA soft surface-enhanced Raman scattering (SERS) substrate was fabricated based on a three-dimensional (3D) structure of biocompatible end-tethered poly(l-lysine) (“t-PLL”) with a brushlike configuration conjugated with silver nanoparticles (Ag NPs) (Ag NP-t-PLL film). The conjugation procedures were carefully adjusted to generate the films with different interval widths (W) between Ag NPs and diameters (D) of Ag NPs. The resulting film was then characterized by zeta potential, CD spectropolarimeter, and scanning electron microscopy. Furthermore, the studies of SERS enhancements using Ag NP-t-PLL film as a substrate were performed. The significant increases of SERS enhancements have been obtained as W/D was decreased from 0.9 to 0.2. Our results not only afford a facile fabrication of a 3D soft substrate for SERS with high sensitivity and biocompatibility but also offer great potentials for the development of new biosensors.Item Platinum-Decorated Ruthenium Nanoparticles for Enhanced Methanol Electrooxidation(Wiley-VCH Verlag, 2010-02-08) C.-H. Chen; L. S. Sarma; D. -Y. Wang; F.-J. Lai; C.-C. AI Andra; S.-H. Chang; D.-G. Liu; Chia-Chun Chen; J.-F. Lee; B.-J. HwangA promising electrocatalyst based on the reduction of Pt2+ ions on the surface of hexagonally close-packed (hcp) Ru core nanoparticles has been prepared by a redox–transmetalation process. This simple synthetic process generates a Pt-on-Ru catalyst with a lower Pt content than commercially available Pt[BOND]Ru electrocatalysts and with a long-range ordered hcp structure, which can significantly reduce the Pt loading. X-Ray absorption spectroscopy of the Pt-on-Ru catalyst reveals pronounced electronic modifications when compared to the commercial Pt[BOND]Ru black catalyst. The Pt-on-Ru catalyst exhibits a higher mass-specific current than the Pt[BOND]Ru black catalyst in solution in 0.5 m H2SO4 with 10 vol. % CH3OH under the conditions of rotating disk experiments. Further optimization of this synthetic procedure may yield even more active electrocatalysts with a significant reduction in noble metal loadings.Item Chemical Transformation from FePt to Fe1-xPtMx (M = Ru, Ni, Sn) Nanocrystals by a Cation Redox Reaction: X-ray Absorption Spectroscopic Studies(American Chemical Society, 2007-02-14) D.-Y. Wang; C.-H. Chen; H.-C. Yen; Y.-L. Lin; P.-Y. Huang; B.-J. Hwang; Chia-Chun ChenNew ternary metal nanocrystals of Fe1-xPtMx (M = Ru3+, Sn2+, or Ni2+) were synthesized by chemical transformation from FePt nanocrystals using a cation redox reaction in a solution. The structure and composition of resulting nanocrystals were characterized by high-resolution transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoemission spectroscopy (XPS). Moreover, X-ray absorption near-edge spectroscopy (XANES) was employed to confirm the chemical transformation from FePt to Fe1-xPtRux nanocrystals. The analyses of extended X-ray absorption find structure (EXAFS) revealed the detailed binding structures and coordination numbers of both FePt and Fe1-xPtRux nanocrystals. The results suggested that iron atoms of FePt lattices were oxidized to be Fe2+ and Fe3+ ions and were replaced by ruthenium atoms from the reduction of Ru3+ ions in solution to form Fe1-xPtRux lattices. Our method has opened a new route to easily and rapidly prepare a solid-solution type of ternary metal nanocrystals for catalytic applications.Item Optical Characterization of Wurtzite Gallium Nitride Nanowires(American Institute of Physics(AIP) Publishing, 2001-11-26) M.-W. Lee; H.-Z. Twu; Chia-Chun Chen; C.-H. ChenThe optical properties of the gallium nitride(GaN)nanowires are examined by the transmission method in the ultraviolet-visible range (1–5 eV) and by the reflection method in the infrared range (500–4000 cm−1). The absorption edge of the GaNnanowires is blueshifted by 0.2 eV from the bulk edge. The temperature dependence of the energy gap is expressed by, Eg(T)=3.724−9.97×10−4/(861+T) eV. The plasma frequency and the free-carrier density of the GaNnanowires, deduced from the infrared reflectance minima, are estimated to be ωp=1100±120 cm−1 and nf=3.73×1017 cm−3, respectively. Obtaining the free-carrier density from the infrared reflectance spectra is especially useful in research on nanostructured semiconductors.Item Catalytic Growth and Characterization of Gallium Nitride Nanowires(American Chemical Society, 2001-03-28) Chia-Chun Chen; C.-C. Yeh; C.-H. Chen; M.-Y. Yu; H.-L. Liu; J.-J. Wu; K.-H. Chen; L.-C. Chen; J.-Y. Peng; Y.-F. ChenThe preparation of high-purity and -quality gallium nitride nanowires is accomplished by a catalytic growth using gallium and ammonium. A series of catalysts and different reaction parameters were applied to systematically optimize and control the vapor−liquid−solid (VLS) growth of the nanowires. The resulting nanowires show predominantly wurtzite phase; they were up to several micrometers in length, typically with diameters of 10−50 nm. A minimum nanowire diameter of 6 nm has been achieved. Temperature dependence of photoluminescence spectra of the nanowires revealed that the emission mainly comes from wurtzite GaN with little contribution from the cubic phase. Moreover, the thermal quenching of photoluminescence was much reduced in the GaN nanowires. The Raman spectra showed five first-order phonon modes. The frequencies of these peaks were close to those of the bulk GaN, but the modes were significantly broadened, which is indicative of the phonon confinement effects associated with the nanoscale dimensions of the system. Additional Raman modes, not observed in the bulk GaN, were found in the nanowires. The field emission study showing notable emission current with low turn-on field suggests potential of the GaN nanowires in field emission applications. This work opens a wide route toward detailed studies of the fundamental properties and potential applications of semiconductor nanowires.Item Preparation and Characterization of Carbon Nanotubes Encapsulated GaN Nanowires(Elsevier, 2001-09-10) Chia-Chun Chen; C.-C. Yeh; C.-H. Lang; C.-C. Lee; C.-H. Chen; M.-Y. Yu; H.-L. Liu; L.-C. Chen; Y.-S. Lin; K.-J. Ma; K.-H. ChenA novel two-step catalytic reaction is developed to synthesize gallium nitride nanowires encapsulated inside carbon nanotubes (GaN@CNT). The nanowires are prepared from the reaction of gallium metal and ammonium using metals or metal alloys as a catalyst. After the formation of the nanowires, carbon nanotubes are subsequently grown along the nanowires by chemical vapor deposition of methane. The structural and optical properties of pure GaN nanowires and GaN@CNT are characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy and Raman spectroscopy. The results show that GaN nanowires are indeed encapsulated inside carbon nanotubes. The field emission studies show that the turn-on field of GaN@CNT is higher than that of carbon nanotubes, but substantially lower than that of pure GaN nanowires. This work provides a wide route toward the preparation and applications of new one-dimensional semiconductor nanostructures.Item Infrared and Raman-Scattering Studies in Single-Crystalline GaN Nanowires(Elsevier, 2001-09-14) H.-L. Liu; Chia-Chun Chen; C.-T. Chia; C.-C. Yeh; C.-H. Chen; M.-Y. Yu; S. Keller; S. P. DenBaarsInfrared and Raman-scattering studies of high-purity and -quality GaN nanowires are presented. The nanosize dependences of the peak shift and the broadening of the four first-order Raman modes agree with those calculated on the basis of the phonon confinement model. Additionally, the appearance of one Raman mode at ∼View the MathML source is attributed to zone-boundary phonon activated by surface disorders and finite-size effects. Moreover, the Raman-scattering intensities of certain phonons show a different resonantly enhanced behavior, which can be used to verify the information on the electronic structures and the electron–phonon interaction in GaN nanowires.