Browsing by Author "Wang, Yun-Hsin"

Now showing 1 - 2 of 2

Autothermal steam reforming of ethanol over La2Ce2-xRuxO7 (x=0-0.35) catalyst for hydrogen production
(2013-05-02)
Weng, Sheng-Feng
;
Wang, Yun-Hsin
;
Lee, Chi-Shen
;
應用化學系
;
Department of Applied Chemistry
Pyrochlore phases solid solutions, La2Ce2-xRuxO7 (x=0-0.35) were prepared with a sol-gel process and used as catalysts for the autothermal steam reforming of ethanol. The samples as prepared were characterized with powder X-ray diffraction (PXRD), X-ray photoelectron spectra (XPS), and temperature-programmed reduction (TPR). The XPS and TPR spectra revealed the effect of doped Run+ to oxidation states of La and Ce sites. The low temperature reduction ability and relative concentration of Ce4+ ions are increased as the cell-dimension decreased. Tests of catalytic activity showed that the reforming performance of La2Ce2-xRuxO7 catalysts was affected by the Ru/Ce loading ratio. For all catalysts, partial oxidation was favored at a large C/O composition; incomplete ethanol conversion was observed for C/O >= 0.7. The optimized catalyst was La2Ce1.8Ru0.2O7 with hydrogen production rate (r(H2)) 2.01 x 10(-3) mol s(-1) g(cat)(-1) (autothermal temperature similar to 600 degrees C and 97% ethanol conversion at C/O=0.6). The catalyst exhibited stable r(H2) over 26 h of the reaction with ethanol conversion >95%. r(H2) of the catalyst gradually decreased thereafter because LaAlO3 started to formed and affected catalytic process. For the catalyst, the Ru ions remained well dispersed before and after the AESR reaction. (C) 2013 Elsevier B.V. All rights reserved.
New metal-organic frameworks of [M(C6H5O7)(C6H6O7)(C6H7O7)(H2O)] center dot H2O (M=La, Ce) and [Ce-2(C2O4)(C6H6O7)(2)] center dot 4H(2)O
(2012-04-01)
Weng, Sheng-Feng
;
Wang, Yun-Hsin
;
Lee, Chi-Shen
;
應用化學系
;
Department of Applied Chemistry
Two novel materials, [M(C6H5O7)(C6H6O7)(C6H7O7)(H2O)] center dot H2O (M=La(1a), Ce(1b)) and [Ce-2(C2O4) (C6H6O7)(2)] center dot 4H(2)O (2), with a metal-organic framework (MOF) were prepared with hydrothermal reactions and characterized with photoluminescence, magnetic susceptibility, thermogravimetric analysis and X-ray powder diffraction in situ. The crystal structures were determined by single-crystal X-ray diffraction. Compound 1 crystallized in triclinic space group P (1) over bar (No. 2); compound 2 crystallized in monoclinic space group P2(1)/c (No. 14). The structure of 1 is built from a 1D MOF, composed of deprotonated citric ligands of three kinds. Compound 2 contains a 2D MOF structure consisting of citrate and oxalate ligands; the oxalate ligand arose from the decomposition in situ of citric acid in the presence of Cu-II ions. Photoluminescence spectra of compounds 1b and 2 revealed transitions between the 5d(1) excited state and two levels of the 4f(1) ground state (F-2(5/2) and F-2(7/2)). Compounds 1b and 2 containing Ce-III ion exhibit a paramagnetic property with weak antiferromagnetic interactions between the two adjacent magnetic centers. (C) 2012 Elsevier Inc. All rights reserved.