Muneyuki Tsuda

Publications (3)7.53 Total impact

• Article: Comparative study of O2 dissociation on various metalloporphyrins.

  Muneyuki Tsuda, Eben Sy Dy, Hideaki Kasai
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  ABSTRACT: We investigate O(2) interaction with various metalloporphyrins (MnP, FeP, CoP, and NiP) using ab initio calculations based on density-functional theory. We discuss the trends in the activation barriers for the O-O bond cleavage in relation to the geometric, vibrational, electronic, and energetic properties of the systems. Whether the lowest unoccupied molecular orbital-highest occupied molecular orbital (LUMO-HOMO) levels of the metalloporphyrins involve the corresponding metal centers depends on the d orbital occupancies of the metals. We found that activation barriers for the O(2) dissociation can be mainly determined from the LUMO-HOMO characters of the metalloporphyrins, and consequently the FeP is the best catalyst with respect to the O(2) interaction from adsorption to dissociation.
  The Journal of Chemical Physics 07/2005; 122(24):244719. · 3.33 Impact Factor
• Article: Cyclohexane dehydrogenation catalyst design based on spin polarization effects

  Muneyuki Tsuda, Agerico Diño, Susumu Watanabe, Hiroshi Nakanishi, Hideaki Kasai
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  ABSTRACT: We investigate and discuss spin polarization effects on cyclohexane (C6H12) dehydrogenation using a Ni atom as a test catalyst, by performing total energy calculations based on the density functional theory (DFT). We compare the results with those of the well known catalyst Pt. We consider the process where cyclohexane approaches a transition metal M (M: Ni and Pt), and determine the reaction paths from the calculated potential energy surfaces (PESs) for singlet cyclohexane/M and triplet cyclohexane/Ni systems. Unlike the singlet cyclohexane/Ni, no energy is required to separate cyclohexyl intermediate (C6H11) from the H–Ni system for the triplet cyclohexane/Ni. Our results suggest that the catalytic reactivity of spin-polarized Ni becomes close to that of Pt, which is considered to be, up to now, the best catalyst for cyclohexane dehydrogenation.
  Journal of Physics Condensed Matter 11/2004; 16(48):S5721. · 2.55 Impact Factor
• Article: Behavior of hydrogen atom at Nafion–Pt interface

  Muneyuki Tsuda, Wilson Agerico Diño, Hideaki Kasai
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  ABSTRACT: We present a mechanism depicting how a hydrogen atom migrates from a platinum catalyst to a Nafion membrane using ab initio calculations based on density functional theory (DFT). The H atom initially adsorbed on Pt is extracted by the sulfonate group (–SO3−), which is a part of the side chain of Nafion. We found partial electron transfer from the H atom to the Pt, which directly binds to the –SO3− group, through this reaction. The electron-poor H atom conducts in Nafion, and the partial electron transfer from the H atom results in the generation of electric power in polymer electrolyte fuel cells (PEFCs).
  Solid State Communications 134(9):601-605. · 1.65 Impact Factor