Browsing by Author "Hsieh, Ho-Chen"

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Degradable NIR-PTT Nanoagents with a Potential Cu@Cu2O@Polymer Structure
(2018-02-14)
Tai, Yu-Wei
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Chiu, Yi-Chun
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Wu, Po-Ting
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Yu, Jiashing
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Chin, Yu-Cheng
Cu@Cu2O@PSMA polymer nanoparticles (Cu@Cu2O@polymer NPs) with near-infrared (NIR) absorption were successfully synthesized in a single-step oxidation reaction of Cu@PSMA polymer NPs at 100 degrees C for 20 min. The shape, structure, and optical properties of the Cu@Cu2O@polymer NPs were tailorable by controlling the reaction parameters, for example, using the initial Cu@PSMA polymer NP as a template and varying the halide ion content, heating temperature, and reaction time. The Cu@Cu2O@polymer NPs exhibited robust NIR absorption between 650 and 710 nm and possessed superior oxidation resistance in water and culture media. In vitro assays demonstrated the low cytotoxicity of the Cu@Cu2O@PSMA polymer NPs to HeLa cells through an improved cell viability, high IC50, low injury incidence from the supernatant of the partly dissociated Cu@Cu2O@PSMA polymer NPs, and minor generation of reactive oxygen species. More importantly, we demonstrated that the inorganic Cu-based nanocomposite [+0.34 V vs normal hydrogen electrode (NHE)] was degradable in an endogenous H2O2 (+1.78 V vs NHE) environment. Cu ions were detected in the urine of mice, which illustrates the possibility of extraction after the degradation of the Cu-based particles. 'After an treatment of the HeLa cells with the Cu@Cu2O@polymer NPs and a 660 nm light-emitting diode, the photoablation of 50 and 90% cells was observed at NP doses of 20 and 50 ppm, respectively. These results demonstrate that NIR-functional and moderate redox-active Cu@Cu2O@polymer NPs are potential next-generation photothermal therapy (PTT) nanoagents because of combined features of degradation resistance in the physiological environment, enabling the delivery of efficient PTT, a possibly improved ability to selectively harm cancer cells by releasing Cu ions under high-H2O2 and/or low-pH conditions, and ability to be extracted from the body after biodegradation.
Hydrogen production from oxidative steam reforming of ethanol on nickel-substituted pyrochlore phase catalysts
(2017-02-02)
Weng, Sheng-Feng
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Hsieh, Ho-Chen
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Lee, Chi-Shen
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應用化學系
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Department of Applied Chemistry
A series of Ni-substituted pyrochlore oxides of La2Ce2-x NixO(7-delta) (x = 0.0-0.45) is prepared and their catalytic performance is studied. All compounds are characterized by X-ray powder diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) and temperature-programmed reduction (TPR). Based on the XRD and XPS analyses, Ni is incorporated into the pyrochlore structure and induces the formation of Ce3+ ions. The reduction behavior and catalytic performance are directly related to the Ni content. The H-2 consumption in the TPR and H-2 production increases with the increased Ni content. The catalytic properties of these catalysts in the oxidative steam reforming of ethanol (OSRE) are investigated. The highest catalytic activity is obtained for the x = 0.45 sample, with a hydrogen selectivity of 82.60(5)% and the most stable catalyst is x = 0.2 with an average hydrogen selectivity of 79.0(4)%. The improved catalytic behavior can be attributed to the synergetic effect of cerium and nickel ions in the pyrochlore framework, which induces oxygen vacancies and reduces carbon formation. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Metal substituted pyrochlore phase LixLa2-xCe1.8Ru0.2O7- (x=0.0-0.6) as an effective catalyst for oxidative and auto-thermal steam reforming of ethanol
(2019-03-21)
Hsieh, Ho-Chen
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Chang, Yuan-Chia
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Tsai, Ping-Wen
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Lin, Yen-Yu
;
Chuang, Yu-Chun
Pyrochlore phase LixLa2-xCe1.8Ru0.2O7- (x = 0.0-0.6) [LLCRO] substituted by Li and Ru in A and B sites was synthesized and studied for performance in oxidative steam and auto-thermal reforming of ethanol (OSRE, ATR). The samples were characterized by powder X-ray diffraction (PXRD), X-ray absorption spectroscopy (XAS), and X-ray photoelectron spectroscopy (XPS) to examine the effect of substituted Li+ and Run+ on OSRE performance. The results indicated that the substituted Li ions modified the oxidation states of Ru and Ce in LLCRO, which led to oxygen vacancies/mobility and played an important role in the catalytic performance of OSRE. Using LLCRO as the catalyst and supported by Al2O3, La2Zr2O7 (LZO) was investigated for its hydrogen production performance. The catalytic stability of the LLCRO (x = 0.6)/LZO catalysts was tested at 350 degrees C under oxidative steam conditions (OSRE) and showed a stable ethanol conversion and hydrogen production (X-EtOH = 98(3)%; S-H2 = 95(3)%). Under autothermal conditions (ATR), the LLCRO (x = 0.6) catalyst supported by LZO exhibited a stable catalytic performance with an average ethanol conversion and hydrogen selectivity of 90(3)% and 71(4)%, respectively. Carbon deposition was significantly suppressed during the OSRE and ATR processes on LLCRO (x = 0.6) catalysts supported by LZO, whereas, a significant carbon deposition was observed for LLCRO (x = 0.6)/Al2O3 as the catalyst. These results indicate that LLCRO (x = 0.6) supported by LZO is an effective catalyst for hydrogen production. The enhanced activity was attributed to the effectively suppressed carbon deposition and the sintering of highly dispersed Ru ions in the LLCRO catalyst, which may be due to the strong binding between the catalyst and LZO.
Oxidative steam reforming of ethanol over MxLa2-xCe1.8Ru0.2O7-delta (M = Mg, Ca) catalysts: effect of alkaline earth metal substitution and support on stability and activity
(2019-12-02)
Hsieh, Ho-Chen
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Tsai, Ping-Wen
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Chang, Yuan-Chia
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Weng, Sheng-Feng
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Sheu, Hwo-Shuenn
Alkaline earth metal substitutions on the A-site of pyrochlore oxide MxLa2-xCe1.8Ru0.2O7-delta (M = Mg, Ca) were studied as catalyst materials for oxidative/autothermal steam reforming of ethanol (OSRE/ATR). The as-prepared oxides were synthesized by a combustion method and characterized using powder X-ray diffraction (PXRD), and X-ray photoelectron and absorption spectroscopy (XPS and XAS). PXRD Rietveld analysis and elemental analysis (ICP-AES) support the formation of a pyrochlore-type structure (space group Fd3m) with a distorted coordination environment. The substitution of Mg²⁺ and Ca²⁺ ions affects the oxidation states of Ce^4+/3+ and Ruⁿ⁺ ions and creates oxygen vacancies, which leads to enhanced catalytic activity and reduced ethylene selectivity. A long-term stability test showed optimized catalysts Mg0.3La1.7Ce1.8Ru0.2O7-delta and Ca0.2La1.8Ce1.8Ru0.2O7-delta with SH2 = 101(1)% and SH2 = 91(2)% under OSRE conditions. The initial operation temperatures were lower than that of the unsubstituted catalyst La2Ce1.8Ru0.2O7-delta. Catalysts supported on La2Zr2O7 showed stable OSRE/ATR performance and low carbon deposition compared to catalysts supported on Al2O3. We ascribe the enhanced activity to well-dispersed alkaline earth metal and Ru ions in a solid solution structure, synergistic effects of (Mg, Ca)²⁺/Ce^3+/4+/Ruⁿ⁺ ions, and a strong catalyst-support interaction that optimized the ethanol conversion and hydrogen production.
Ruthenium substituted pyrochlore metal oxide catalysts Y2Ce2-xRuxO7-delta (x=0-0.4) for oxidative steam reforming of ethanol
(2020-07-31)
Hsieh, Ho-Chen
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Chen, Yun-Sheng
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Weng, Sheng-Feng
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Hsieh, Yu-Ping
;
Lee, Chi-Shen
Metal oxides Y2Ce2-xRuxO7-delta (x = 0-0.4) with partial substitution of Run+ cations in the host structure were synthesized to study their catalytic activity on oxidative steam reforming of ethanol (OSRE). The samples were characterized using X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and temperature-programmed reduction (TPR). The performances investigated by varied temperatures, Ru ion content, carbon-to-oxygen ratios and long-term stability. The lowest activation temperature on OSRE is 300 degrees C, which is significantly lower than that of La2Ce2-xRuxO7-delta (400 degrees C). The cell dimension of Y2Ce2-xRuxO7-delta was reduced compare to La2Ce2-xRuxO7-delta for the replacement of the Y3+ ion with La3+ ion. The reduced unit cell in the host structure not only increase the surface composition of the Ce4+ ions, but also induce the synergetic effect of Run+/Ru4+ (n > 4) and Ce4+/Ce3+, which lead to the enhanced OSRE activity. The optimized catalyst Y2Ce1.6Ru0.4O7-delta showed selectivity of hydrogen S-H2 = 84(4)% (Y-H2 = 2.5(1) mol/mol EtOH) and carbon monoxide S-CO = 48(1)% for long-term stability test at T = 300 degrees C, C/O = 0.5, and O-2/C2H5OH = 1.5. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.