第一原理計算に基づくメタノール熱面着火の表面金属種依存性の解析

抄録

First-principle computations were performed to investigate the methanol surface reactions on various metal surfaces. The adsorption energy of methoxy intermediate was shown to be dependent on the electronegativity of surface atoms. This was found to affect the reaction pathway and the reactivity of surface methanol reactions. It was confirmed that surfaces composed of high electronegativity atoms, such as Pt, destabilize the methoxy intermediate and increase the total methanol decomposition rate. The effect of surface oxygen atom on the methanol decomposition was also investigated. It was found that the surface oxygen atoms promote O-H bond scission and hinder C-H bond scission. Based on the first-principle computational results, methanol/Pt surface reaction model was constructed and used to investigate the mechanism behind the hot-surface ignition of methanol/oxygen mixture. Numerical simulation using combined gas-phase and gas-surface reaction model showed that hot Pt surface highly promotes the ignition of the methanol/oxygen mixture, but only slight promotion was observed in the case of methane/oxygen mixture. The cause of the difference was found to be the rate of heat production due to fuel oxidation reaction at Pt surface.