大阪大学 · Materials Science
요시다 모리카와 교수의 연구실은 밀도함수이론(DFT) 기반의 첫 번째 원리 계산을 활용해 표면화학 반응과 분자-표면 상호작용을 깊이 있게 연구하고 있습니다. 주요 연구 분야로는 금속 및 산화물 표면에서의 분자 흡착 거동, 산화물 촉매 반응 메커니즘, 전자구조 변화와 일함수 변화의 기전을 다룹니다. 특히, 이산화티타늄(TiO2)과 실리콘(Si) 표면에서의 산화 및 탈수 반응, 알카인 및 알케인의 표면 거동 등에서의 정량적 분석을 통해 실험 결과와의 정합성을 확보하고 있습니다. 이는 고체표면의 촉매성능 향상 및 전자물성 제어에 기여하는 기초 연구입니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
The interaction between n-alkane and metal surfaces has been studied by means of density-functional theoretical calculations within a generalized gradient approximation (GGA). We demonstrate that although the GGA cannot reproduce the physisorption energy well, our calculations can reproduce the experimentally observed work-function change and softening of the CH stretching mode reasonably well. We also show that the most significant factor determining their dependence on metal substrates is the
Adsorption geometries and vibrational modes of ${\mathrm{C}}_{2}{\mathrm{H}}_{2}$ on the Si(001) surface are studied by means of density-functional theory within the generalized gradient approximation. By comparing theoretically calculated high-resolution electron-energy-loss spectra with experimentally reported spectra, it is clearly shown that at least two energetically most stable adsorption states coexist.
We have studied oxygen and potassium coadsorption on the Si(001) surface with first-principles molecular dynamics. The present calculation gives a strong support to the structural model based on double-layer K adsorption. Oxygen adsorption on the K/Si(001) surface reduces the work function by 0.7 eV and activates the negative electron affinity in accord with experimental results. The oxygen atoms are adsorbed slightly below the potassium atoms and accumulate a valence charge around the surface r
We have studied the dehydration process of formic acid on a TiO2(110) surface by using first-principles theoretical calculations. Formic acid dissociatively adsorbs to form formate and hydroxyl. It turns out that simple decomposition processes of the formate on the stoichiometric surface are energetically unfavorable. The formation of H2O and O vacancies from two neighboring bridging hydroxyls is relatively easy and the activation barrier is calculated to be 114 kJ/mol. On the TiO2(110) surface
