| Summary: | 碩士 === 國立交通大學 === 應用化學系碩博士班 === 108 === In previous study, we successfully synthesized the optimized solid solution La2Ti1.7Ru0.3O7 by sol-gel method and use it as a catalyst for oxidative steam reforming of ethanol(OSRE) reaction. In this research, we use the same method and successfully synthesized a series of La2-xMxTi1.7Ru0.3O7(M=Mg, Ca, Sr) catalysts. Due to the impurity phase RuO2 formed in La1.8Mg0.2Ti1.7Ru0.3O7, the characterization and performance study were focusing on La2-xMxTi1.7Ru0.3O7(M=Ca, Sr). According to powder X-ray diffraction(PXRD) and Rietveld structure refinement, the phase width of La2-xMxTi1.7Ru0.3O7(M=Ca, Sr) catalyst is between 0~0.2. X-ray Photoelectron Spectroscopy(XPS) and Temperature-Programmed Reduction(TPR) study indicates the relative percentage of high ruthenium oxidation state (Ru≥4+) decreased and the oxygen vacancy increased as the content of Ca, Sr increased. In the performance test, we fixed the C/O ratio at 0.7 and 300°C, and utilized OSRE reaction and 100 hour time on stream test under autothermal steam reforming of ethanol (ATRE) to evaluate the catalyst activity. In OSRE reaction, the results indicated the substitution of Ca and Sr can promote water gas shift reaction (WGS) reaction effectively. The order of WGS activity on catalysts is: La1.8Sr0.2Ti1.7Ru0.3O7 > La1.8Ca0.2Ti1.7Ru0.3O7 > La2Ti1.7Ru0.3O7. The used catalysts La1.8M0.2Ti1.7Ru0.3O7(M=Ca, Sr)/LZO and La2Ti1.7Ru0.3O7/LZO were not decomposed. The catalyst La1.8Sr0.2Ti1.7Ru0.3O7/LZO exhibits the highest ethanol conversion during the time on stream test and there is no sign of carbon deposition on used catalyst.
The second part of this thesis contains the Diffused Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) study on the effect of support on reaction routes of nickel catalyst under different steam/ethanol ratio. The result indicates that using La2Zr2O7 as supporting material could promote methane steam reforming and water gas shift reaction effectively, which prevent the deposition of methane and carbon monoxide on the catalyst. On the other hand, using Al2O3 as supporting material shows low activity on the conversion of C1, C2 intermediate.There are significant amount of methane, carbon monoxide, and acetate attached on the surface of catalyst at high temperature(T=450~500°C) and thus promote the probability on deactivation of the catalyst. Therefore, La2Zr2O7 is a appropriate supporting material for metal or metal oxide catalyst.
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