Cu underpotential deposition

Figure 17. Cyclic voltammograms of Cu underpotential deposition on Au( 111) in 90mAf H2SO4 + xM CUSO4 x =...

An in situ EUR study of bisulfate and sulfate adsorption indicated that the coverage of adsorbed sulfate increased in the presence of Cu underpotential deposition on polycrystalline Au. ... 

EQCM frequency of 20 Hz, which corresponds to a one-third monolayer of sulfate species adsorption/desorption. However, the electricity from the above cyclic voltammogram current is calculated to be about 1 x 10 C ctn i.e., 6 x 10 molecules cin" which is about one-tenth of a monolayer. This may indicate that sulfate adsorption on Au(lll) is associated with a partial charge transfer process. In Fig. 25b, an increase in EQCM frequency was observed as for (a), and a decrease in the frequency was observed at the Cu underpotential deposition region. The frequency change due to Cu underpotential deposition is determined to be 35 Hz,... 

Rotating ring-disk electrodes were employed for an anion effect on the Cu underpotential deposition on Pt(lll) in fluoric and perchloric acid solutions, the results of which were discussed in comparison with UHV results of AES and LEED. ... 

An ex situ EXAFS study was conducted for Cu underpotential deposition on polycrystalline Pt in 0.2mM CUSO4 + 0.5M H2SO4. The iodine-treated Pt was subjected to Cu underpotential deposition, the features of which were observed by EXAFS. ° An EXAFS study of Cu... 

Figure 26. The cyclic voltammogratn of Cu underpotential deposition at 10 mV s onPt(lll)inO.IMH2S04+ [mMCuSO ...

STM images of Ag underpotential deposition on Pt(lll) were observed as (1 X 1) and (VJx V3) structures at the potentials of Ag mono-layer formation and between two underpotential deposition peaks, respectively." The STM image at Pt(lOO) was examined for Cu underpotential deposition in the presence of halide ions in sulfuric acid solution... 

EXAFS results, Cu atoms locate on the top of Pt atoms. Experimental and theoretical EXAFS studies were carried out for Cu underpotential deposition on Pt(lll) in a 0.1 M H2SO4 -1- SQ/iM Cu " solution, giving the position of copper underpotential deposition at three hollow sites of Pt(lll), which is partially positively charged. ... 

In situ FTIR for Cu underpotential deposition on Pt( 111) and Rh (111) was observed in sulfuric and perchloric acid solutions." Both adsorbed sulfate and perchlorate species were found on underpotential deposition Cu. The underpotential deposition of T1 on Pt( 111) was observed by FTIR in view of the coadsorption of pachlorate and bisulfate.The IR bands of the adsorbed anions were found to be due to the presence of underpotential deposition metals on Pt(lll), and the possibility of the presence of an ion pair of the underpotential deposition metal and an anion is discussed. 

For the Cu underpotential deposition peak at the positive potential-side on Au(l 11) in sulfuric acid solution, the slope of peak potentials with... 

Ex situ LEED and XPS studies were conducted to demonstrate the effects of CUand Br" these anions form densely packed incommensurate structures on Cu underpotential deposition at the full monolayer. ... 

A kinetic study of Cu underpotential deposition was carried out to determine if it is best described by adsorption processes or by nucleation processes. The nucleation growth process is classified into two categories instantaneous nucleation growth and progressive nucleation growth. In the case of instantaneous nucleation growth, where nucleation site formation is so fast that no other following nucleation sites are created, the number of nucleation sites N(t) is expressed as... 

Figure 42. (a) Cyclic voltammogram at 1 mV s on Au( 111) in 0.05M H2SO4 + 1 mM CUSO4. (b) Electrochemically derived Cu underpotential deposition coverage as a function of potential, determined by potential steps in the positive direction. The Cu underpotentia) deposition structures obtained from LEED and RHEED are also shown. (From Ref. 142.)... 

Figure 43. Plot of current against time for peaks A, A, B, and B of the cyclic voltammogram for Cu underpotential deposition. Potential steps are indicated in the figures. Details are in the text. (From Ref. 142.)...

The characteristics of monatomic height step formation ofCu under-potential deposition on Ag(l 11) in sulfuric acid solution were observed to be dependent on electrode potentials/ At more positive underpotential deposition potential regions, STM revealed the frizzy edges of Cu underpotential deposition at the comers of Cu islands growing on the Ag( 111) terrace STM. The kink site mobility was roughly estimated as 3000 nm s . Monatomic height steps on Au(l 11) electrodes did not show any sign of frizziness under the experimental condition. ... 

Silver deposition on polycrystalline Pt electrodes at potentials positive to the equilibrium potential gave 2.5 atomic layers. Two binding types of Ag layers were found by anodic stripping the first Ag layer deposited on Pt, which seems to form an alloy of Ag-Pt, on which the second Ag deposition takes place in the Ag underpotential deposition region. STM images from the underpotential to the overpotential deposition region were observed for Cu underpotential deposition on Au(l 11) in sulfuric acid solution, where Cu underpotential deposition does not affect overpotential deposition, although the latter always takes place on the surface with Cu underpotential deposition and a metal. ... 

The effect of acetate, citrate, and thiourea on Pb underpotential deposition on Ag(lll) has been studied. The effects of the anionic character of the additives were discussed in relation to changes in voltammograms. The two-dimensional phase transformation was also discussed. The influence of various additives such as dimethylfluoride (DMF) and pyridine on cyclic voltammograms of Cu underpotential deposition on Pt(lll) was observed. Cu underpotential deposition on Pt(lll) was studied in the presence of crystal violet, coumarin, and hydroquinone. ... 

The addition of crystal violet to a Cu underpotential deposition systen on Au(l 11) gave two different STM images at potentials different from the images seen in its absence. One of these was due to the presence of Cr as a counteranion in the crystal violet molecule. Thiourea was added to Cu underpotential deposition on Au(lll) to investigate the... 

Figure 16.3.3 AFM study of Cu underpotential deposition (UPD) on an Au(l 11) electrode surface in 1 mM Cu solution at different potentials. (A) At +0.7 V, showing Au(lll) substrate (B) At —0.1 V, Cu bulk deposition (C) close packed overlayer of Cu at +0.114 V in 0.1 M HCIO4 (D) schematic representation of incommensurate close-packed overlayer of Cu (striped atoms) on Au substrate (light atoms) (E) (V3 X Vs) R30° overlayer of Cu on Au observed at +0.144 V in 0.1 M sulfate solution (F) schematic representation of Cu overlayer shown in (E). [Reprinted with permission from S. Manne, P. K. Hansma, J. Massie, V. B. Elings, and A. A. Gewirth, Science,...

Behm R J, Flotlos J and Magnussen O M 1995 Effect of trace amounts of Cl in Cu underpotential deposition on Au(111) in perchlorate solutions An in situ scanning tunneling microscopy study Surf. Sci. 335 129-44... 

Erikson et al. demonstrated that cubic Pd particles eiuiched with [100] facets with an average size of 27 nm had a higher ORR activity than spherical Pd particles (2.8 nm) [62]. A systematic study on the structural dependence of electrochemical behavior of Pd nanocrystals with a much smaller particle size (5-6 nm) was reported by Shao et al. [63]. As shown in Fig. 17.4a, the hydrogen adsorption peaks were observed at 0.16 and 0.21 V for the Pd cubes and octahedra, respectively [61]. The peak for the Pd cubes was sharper than that for the Pd octahedra. The differences in position and shape of hydrogen peaks may be caused by a weaker adsorption of hydrogen on Pd(lOO) than that on Pd(l 11). The differencebetween Pd cubes and octahedral was also confirmed by their Cu underpotential deposition (UPD) curves (Fig. 17.4b) [61]. For Pd octahedra, a sharp current peak was observed at 0.51 V due to UPD of Cu on 111 facets. On the other hand, a broader... 

Catino EV, Crooks RM (2011) Characterization of Pt Cu core shell dendrimer-encapsulated nanopeuticles synthesized by Cu underpotential deposition. Langmuir 27 4227... 

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