Analysis of Bonding and d-Electron Count in the Transition-Metal Carbides and Transition-Metal-Silicide Carbides with Discrete Linear M−C−M Units (M = Cr, Fe, Re) by Electronic Structure Calculations

1999 ◽  
Vol 38 (9) ◽  
pp. 2204-2210 ◽  
Author(s):  
H.-J. Koo ◽  
M.-H. Whangbo
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Electronic Structure Calculations ◽  
Metal Silicide ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
Transition Metal Silicide ◽  
Structure Calculations

scholarly journals Electronic structure calculations permit identification of the driving forces behind frequency shifts in transition metal monocarbonyls

2020 ◽  
Vol 22 (2) ◽  
pp. 781-798 ◽  
Author(s):  
Elliot Rossomme ◽  
Christianna N. Lininger ◽  
Alexis T. Bell ◽  
Teresa Head-Gordon ◽  
Martin Head-Gordon
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Driving Forces ◽  
Metal Carbonyl ◽  
Electronic Structure Calculations ◽  
Frequency Shifts ◽  
Structure Calculations

Our direct DFT decomposition of CO frequency shifts updates the paradigm for metal carbonyl binding.

Electrochemical Reactions, Chemical Ordering Effects, and Calculated Electronic Structure, for Pt100-xMx (M = V, Zr) Thin-Film Surfaces in Acid Electrolytes

MRS Advances ◽  
2017 ◽  
Vol 2 (8) ◽  
pp. 459-464
Author(s):  
Charles C. Hays ◽  
Uichiro Mizutani
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Fermi Energy ◽  
Short Range ◽  
Electrode Materials ◽  
Polymer Electrolyte Membrane ◽  
Energy Shift ◽  
Electronic Structure Calculations ◽  
Reduction Reaction ◽  
Structure Calculations

ABSTRACTMicrostructural, chemical, and electrochemical property measurements results, for (111) crystallographically oriented Pt100-xMx (M = V, Zr; 3 < xv < 14; and 4 < xZr < 35, At.%) sputtered thin films are presented, with electronic structure calculations. These Pt-based alloys were prepared to investigate early transition metal (ETM), late-transition-metal (LTM) alloys as potential electrode materials in hydrogen-air polymer-electrolyte-membrane fuel cells (PEMFCs). The Pt100-xMx oxygen-reduction-reaction (ORR) currents peak for 8 < x < 10 atomic percent, so local chemical-short-range-order, may exist; as the peak in ORR activity is commensurate with the strong ordering in Pt8M (M = Ti, V, Zr). The hydrogen under potential deposition (Hupd) at Pt active area, and ORR reaction kinetics, on the alloyed surfaces are composition dependent, suggesting three possible effects: 1) charge transfer from V-(3d)3 [or Zr- (4d)2] states, to the hole in the top of the Pt-(5d)9 band alters the electronic structure at the Fermi energy; 2) alloying Pt with the ETM elements introduces a bi-functional character to the electrode surface, and 3) or the presence of short range chemical order induces a Fermi energy shift. To confirm the 1st and 3rd hypotheses, the electronic structure of Pt8Ti, Pt8V, and Pt8Zr, were calculated using the WIEN2k program package. The electronic structure calculations for ordered Pt8M give strong confirmation of the hypotheses, as they reveal that the Pt8M Fermi energy lies within the Pt-5d anti-bonding band, and also falls into a pseudogap in between the Md bonding and anti-bonding bands. In addition, the Pt8M DOS calculations confirm the presence of a deep pseudogap formed across the Fermi energy for both the Pt-sp and M-sp electrons. These experimental and theoretical results motivate additional studies of the novel Pt8M phases.

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