| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 96 === Periodic, Density Functional Theory (PW91-GGA) calculations are used to study competitive paths for methanol decomposition on rutile-type IrO2(110), 1/2ML Ir/ IrO2(110), and Oxygen rich IrO2(110) surface. The energy barriers for all the elementary steps, starting with O—H scission and proceeding via sequential hydrogen abstraction from the resulting methoxy intermediate, are presented here. The minimum energy path is represented by a potential energy connecting methanol with its final decomposition product, carbon monoxide (CO). For methanol decomposition on IrO2(110) surface, the energy barriers of methoxy dehydrogenation, formaldehyde dehydrogenation, and hydrogen diffusion between Obr are very close and those are higher than other reactions. On Ir/IrO2 surface, there are four possible methanol adsorption structures, and the two most stable structures are used to be the initial state of methanol decomposition on Ir/IrO2 surface. The calculated result shows the adsorption of CHO on the surface with four member ring conformation is very close,which may poison the catalytic surface. The structure of methanol adsorption on IrO2 is different from O/IrO2 . The rate determining step of methanol decomposition on O/IrO2 surface is CHO, and decomposition, the energy barrier is 1.74 eV.
|
|---|
