OH, binding energy

Figure 14.4 Trends in the ORR activity as a function of both the O and OH binding energy. Reproduced with permission from [38].

Electrocatalysis, Fundamentals - Electron Transfer Process Current-Potential Relationship Volcano Plots, Fig. 5 Oxygen reduction activity plotted as a function of both the O and the OH binding energies [14]... 

Analogous two-dimensional plots can also be built against two different descriptors, such as the adsorption bond strength of the two intermediates. In that case the plot is generally shown as a contour plot and is called a volcano surface [14]. Figure 5 shows volcano surface for the activity of different metal catalysts for ORR versus both metal-0 and metal-OH binding energies. 

Figure 2.20. Trends in oxygen reduction activity piotted as a fimction of both the O and the OH binding energy [44]. (Reprinted with permission from J Phys Chem B 2004 108 17886-92. Copyright 2004 American Chemical Society.)...

When nickel hydroxide is oxidized at the nickel electrode in alkaline storage batteries the black trivalent gelatinous nickel hydroxide oxide [12026-04-9], Ni(0H)0, is formed. In nickel battery technology, nickel hydroxide oxide is known as the nickel active mass (see Batteries, secondary cells). Nickel hydroxide nitrate [56171-41-6], Ni(0H)N02, and nickel chloride hydroxide [25965-88-2], NiCl(OH), are frequently mentioned as intermediates for the production of nickel powder in aqueous solution. The binding energies for these compounds have been studied (55). 

It is important to realize that the binding energies of O, OH, and OOH most likely cannot be varied independently by changing the catalyst. When looking deeper into the... 

Figure 9.15 Kinetic current density (squares) at 0.8 V for O2 reduction on supported Pt monolayers in a 0.1 M HCIO4 solution, and the calculated activation energy barriers for O2 dissociation (filled circles) and OH formation (open circles) on PtML/Au(lll), Pt(lll), PtML/ Pd(lll), and PtML/lT(lll). as a function of the calculated binding energy of atomic oxygen (BEo). The current density data for Pt(lll) were obtained fiom [Maikovic et al., 1999] and ate included for comparison. Key 1, Pt]y[L/Ru(0001) 2, Pb /bllll) 3, PtML/Rh(lH)i 4, Ptim,/ Au(lll) 5, Pt(lll) 6, PtML/Pd(lll). Surface coverage is ML O2 in O2 dissociation and ML each for O and H in OH formation. (Reproduced with permission fiom Zhang et al. [2005a].)...

Deconvolution of the XPS spectra for the Ir4/ levels reveals a chemical shift of 1.2 eV for the oxidized Ir species at 1.3 Vsce, indicating that Ir occurs in the valence state IV. Kim et al. [60] and also Hall et al. [76] assigned the binding energy of 62 eV with a chemical shift of 1.1-1.2 eV to Ir02. Work performed by Augustynski et al. [77] lead to the conclusion that the anodic film on Ir is Ir(OH)4, while Peuckert determined the film composition to be IrO(OH)2 [78]. 

The distribution of electronic states of the valence band for the colored film at 1.25 Vsce resembles very much the valence band of pure Ir02 as reported by Mattheiss [93], The maximum of the l2g band occurs at 1.6 eV below EF, the 02p region extends from roughly 4 eV to 10 eV and a finite density of electronic states at the Fermi level. Upon proton (and electron) insertion the l2g band, which can host 6 electrons, is completely filled and moves to a binding energy of 2.5 eV. Simultaneously, the density of states at EF is reduced to zero and an additional structure, indicating OH bond formation, occurs in the 02p band. The changing density of states... 

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