Carbon cyclic voltammograms

Figure 18. Cyclic voltammograms of a polypyrrole film in propylene carbonate containing 0.5 M UCIO4.97...

Fig. 17. Cyclic voltammogram of the water-soluble Rieske fragment from the bci complex of Paracoccus denitrificans (ISFpd) at the nitric acid modified glassy carbon electrode. Protein concentration, 1 mg/ml in 50 mM NaCl, 10 mM MOPS, 5 mM EPPS, pH 7.3 T, 25°C scan rate, 10 mV/s. The cathodic (reducing branch, 7 < 0) and anodic (oxidizing branch, 7 > 0) peak potentisds Emd the resulting midpoint potential are indicated. SHE, standEU d hydrogen electrode.

Fig. 15.6 Cyclic voltammogram of Cu5.5SiFe4SiiT2S32 in 1 M LiBp4 electrolyte of ethylene carbonate and dimethyl carbonate.

Figure 7. Cyclic voltammogram of 7% w/w FePc dispersed on Vulcan XC-72 carbon. The specimen was prepared by mixing the carbon with an FePc solution In pyridine and subsequently removing the solvent by boiling It off. The sample was then heat treated at 300°C In flowing He to remove coordinated pyridine. The cyclic voltammogram was obtained with the material In the form of a thin porous coating In 1 M NaOH at 25 C. Sweep rate 5 mV s (19).

Figure 2. Cyclic voltammograms of ferrl-/ ferro-cyanlde couple at an activated glassy carbon electrode at scan rates of a) 20, b) 50, and c) 100 mV s . See text for details.

Figure 3. Cyclic voltammograms of ascorbic acid at a freshly polished, active (a) and a deactivated (b) glassy carbon electrode surface. See text for details.

Figure 11.11 Linear cyclic voltammograms of carbon-supported nanosized Pt and Pt-Cr alloy catalysts with different atomic ratios (prepared using the carbonyl route [Yang et al., 2004]) recorded in 0.5 M HCIO4 saturated with pure oxygen at a scan rate of 5 mV s and a rotation speed of 2000 rev min Current densities are normalized to the geometric surface...

Figure 11.13 Linear cyclic voltammograms of different carbon-supported catalysts recorded in an 02-saturated electrolyte (0.5 M H2SO4) (1) Pt/C catalyst (2) Pt/C catalyst in the presence of 1.0 M methanol (3) FePc/C catalyst (4) FePc/C catalyst in the presence of 1.0 M methanol (temperature 20 °C, scan rate 5 mV s rotation speed 2500 rev min ).

Figure 17.12 Direct electrocatal3ftic oxidation of D-fnictose at a glassy carbon electrode painted with a paste of Ketjen black particles modified with D-fructose dehydrogenase from a Gluconobacter species. The enzyme incorporates an additional heme center allowing direct electron transfer from the electrode to the flavin active site. Cyclic voltammograms were recorded at a scan rate of 20 mV s and at 25 + 2 °C and pH 5.0. Reproduced by permission of the PCCP Owner Societies, from Kamitaka et al., 2007.

Since model compounds reveal well-defined cyclic voltammograms for the Cr(CNR)g and Ni(CNR)g complexes (21) the origin of the electroinactivity of the polymers is not obvious. A possible explanation (12) is that the ohmic resistance across the interface between the electrode and polymer, due to the absence of ions within the polymer, renders the potentially electroactive groups electrochemically inert, assuming the absence of an electronic conduction path. It is also important to consider that the nature of the electrode surface may influence the type of polymer film obtained. A recent observation which bears on these points is that when one starts with the chromium polymer in the [Cr(CN-[P])6] + state, an electroactive polymer film may be obtained on a glassy carbon electrode. This will constitute the subject of a future paper. 

Figure 1. Cyclic voltammograms at 2mV/s in 2 mol.L 1 KNOs medium for two-electrode capacitors based on a-Mn02 nH20 loaded with 15 wt% of carbon black or carbon nanotubes.

Figure 3. Cyclic voltammograms in three-electrode cells for activated carbon andfor a-MnC>2 nH20 loaded with 15wt% of carbon nanotubes in 2 molL 1 KNO3 medium using Pt as...

Figure 4. Cyclic voltammogram of an asymmetric capacitor with activated carbon and a-MnOynHiO as positive and negative electrodes, respectively, in 2 mol L 1 KNOj medium.

Figure 3.59 Cyclic voltammogram of a glassy carbon electrode immersed in N2-saturated aceto-nitrile/0.2M tetraethylammonium tetrafluoroborate containing 5 x 10 3 M Re(dmbpy)(CO)3Ci, The scan rate is 100mVs 1. From Christensen et at. (1992).

FIGURE 13.2 Typical cyclic voltammogram of Prussian blue-modified smooth (mirrored glassy carbon) electrode 0.1 M KC1, 40mV s 1. 

Concerted Reduction of O and Cu+ or Acr+. Figure 5 illustrates the cyclic voltammograms for O2 in MeCN(0.1M TEAP) at glassy carbon, Cu, Ag, and Au electrodes (each polished immediately prior to exposure to O2). The drawn out reduction waves and the absence of significant anodic peaks upon scan reversal for the three metal electrodes indicate that 02 reacts with the surface prior to electron transfer. 

Figure 1. Cyclic voltammograms in MeCN(0.1M tetra-ethylammonium perchlorate) for the oxidation of (a) a copper electrode, (b) 3 mM "OH at a glassy carbon electrode, (c) 0.5 mM "OH at a copper electrode, and (d) 3 mM "OH at a copper electrode. Scan rate, 0. IV s"1 electrode area, 0.08 cm2 copper electrode prepared by electroplating Cu(C104) onto a glassy carbon electrode (GCE). ...

The product is exclusively carbon monoxide, and good turnover numbers are found in preparative-scale electrolysis. Analysis of the reaction orders in CO2 and AH suggests the mechanism depicted in Scheme 4.6. After generation of the iron(O) complex, the first step in the catalytic reaction is the formation of an adduct with one molecule of CO2. Only one form of the resulting complex is shown in the scheme. Other forms may result from the attack of CO2 on the porphyrin, since all the electronic density is not necessarily concentrated on the iron atom [an iron(I) anion radical and an iron(II) di-anion mesomeric forms may mix to some extent with the form shown in the scheme, in which all the electronic density is located on iron]. Addition of a weak Bronsted acid stabilizes the iron(II) carbene-like structure of the adduct, which then produces the carbon monoxide complex after elimination of a water molecule. The formation of carbon monoxide, which is the only electrolysis product, also appears in the cyclic voltammogram. The anodic peak 2a, corresponding to the reoxidation of iron(II) into iron(III) is indeed shifted toward a more negative value, 2a, as it is when CO is added to the solution. 

Fig. 2 Cyclic voltammograms recorded at a glassy carbon disk electrode (diameter = 1mm) at a sweep rate of lVs-1 in 0.2 M Bu4NPF6/THF for Zn-reduced solutions of...

Fig. 30 Cyclic voltammograms of [57] (1.0 X 10 3 mol dm-3) in acetonitrile in the absence (a) and the presence of 0.3 equiv (b) and 1.0 equiv (c) of sodium cations added as the perchlorate salt. Supporting electrolyte 0.1 mol dm-3 NBU4BF4. Scan rate 100 mV s Working electrode, glassy carbon.

Figure 8 Cyclic voltammograms recorded at a glassy carbon electrode in solution of [(jx-C5H5)Fe(CO)2]2 in (a) MeCN (b) CH2Cl2. Supporting electrolyte [NBu4][PF6], Scan rate 0.25 Vs l...

Cyclic voltammogram recorded at a glassy carbon electrode in a MeCN solution of the 16-metallocene complex illustrated in the scheme. Scan rate 0.1 V s... 

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