Electrocatalytic behavior

For the Pt(llO) electrode, there are some contradictory results regarding its catalytic performance compared with Pt(lOO) some studies indicate that the activity is higher for Pt(llO), whereas others suggest the opposite [Chang et al., 1990 Clavilier et al., 1981 Lamy et al., 1983]. The differences are probably associated with different surface states of the Pt(l 10) electrode. The acmal surface strucmre of the Pt(llO) electrode is strongly dependent on the electrode pretreatment. Since formic acid oxidation is a surface-sensitive reaction, different electrocatalytic behavior can be obtained for the same electrode after different treatments. 

C5Me5)Rhin(L)Cl]+ complexes present a similar electrocatalytic behavior.21,22,25,26,28,29 However, the corresponding Rh-H complex is less stable and could not be isolated, or even characterized, from spectroscopic experiments. 

H. Luo, Z. Shi, N. Li, Z. Gu, and Q. Zhuang, Investigation of the electrochemical and electrocatalytic behavior of single-wall carbon nanotube film on a glassy carbon electrode. Anal. Chem. 73, 915—920... 

Ohsaka s group has extensively examined the electrochemical behavior of both chemically and electrochemically deposited Mn02, both as discrete NPs and as nanostructured interfacial materials [61,64—81]. We focus here on two of their studies that exemplify the electrocatalytic nature of these nanoscale materials. In the first effort, El-Deab and Ohsaka explored the electrocatalytic behavior of MnOOH nanorods that had been electrodeposited onto Pt electrodes by oxidation of Mn(II) in an aqueous solution of manganese acetate [76]. The nanorods had average diameters of 20 nm and aspect ratios of 45 (i.e. average lengths of 900 nm) and covered nearly... 

Pt/Ru electrocatalysts are currently used in DMFC stacks of a few watts to a few kilowatts. The atomic ratio between Pt and Ru, the particle si2 e and the metal loading of carbon-supported anodes play a key role in their electrocatalytic behavior. Commercial electrocatalysts (e.g. from E-Tek) consist of 1 1 Pt/Ru catalysts dispersed on an electron-conducting substrate, for example carbon powder such as Vulcan XC72 (specific surface area of 200-250 m g ). However, fundamental studies carried out in our laboratory [13] showed that a 4 1 Pt/Ru ratio gives higher current and power densities (Figure 1.6). 

This probably means that it entails a common feature leading to the formation of electrodes with ordered domains of single-crystal or stepped surfaces. It is evident that further studies are required to elucidate the mechanism of the process resulting in such systems by simple platinization. For practical reasons, it will be of importance to study the electrocatalytic behavior of these systems. 

The electrocatalytic behavior of Fe6Ge 2W18 toward the reduction of nitrite... 

Electrochemical and electrocatalytic behavior of zinc hexacyanoferrate directly formed on Zn electrode [478] and on carbon substrates [479] were studied. 

Burke LD, O Sullivan JF (1992) A study of electrocatalytic behavior of gold in acid using a.c. voltammetry. Electrochim Acta 37 2087-2094. 

The electrocatalytic behavior of olefins was studied by Zanta et al. (2000) at thermally prepared ruthenium-titanium- and iridium-titanium-dioxide-coated anodes. The aliphatic olefins were shown to be inactive in the region before oxygen evolution, while aromatic ones showed one or two oxidation peaks, and the catalytic activity seemed to be the same for both substrates. However, as for platinum anodes, voltammetric studies and FTIR analyses have also shown the formation of a polymeric film that blocks the surface of the electrode and decreases its activity. 

It is clearly important to know the different electrocatalytic behaviors of some potential DS A anodes and it is also important to obtain the influences of some incorporated elements on the properties of the resulting oxides coatings of DSA anodes. This present chapter focuses on our research related to electrochemical degradation of model substrates - phenol by the Sn02 anode and rare-earth doping Sn02 electrode, including fabrication electrodes, analysis method, and the evaluation of the characteristics of the electrodes. 

Electrocatalytic behavior. The time for lOOmL (100 mg L 1) phenol degradation in 0.25MNa2S04 electrolyte, I = 0.10mAcuT2... 

Element contained in interlayer Electrocatalytic behavior Service life... 

The electrocatalytic behavior of cathodes appears to play a crucial role in the reduction of carbon dioxide. To find more efficient catalysts, detailed mechanistic studies of CO2 reduction are needed. Further studies could also concentrate on the investigation of different electrolytes as well as different catalysts delivering products of choice, such as alcohols. 

During the electrolytic preparation of composite cathodes from solutions of Ni or Co salts with molybdate or tungstate, the current efficiency for deposition of the two metals is far from 1(X)%, so cathodic Hj evolution, with codeposition (sorption) of the H intermediate, is unavoidable. Hence it is virtually certain that these composite cathode materials are formed as hydride materials. It was suggested in Ref. (75) that this may be one of the reasons for their excellent electrocatalytic behavior in the HER, in contrast to that of bulk, thermally prepared alloys of the same metals, Ni and Mo. In this respect, hydrided metals may behave like Pt cathodes where the HER proceeds with good electrocatalysis on a full monolayer of UPD H and, under appreciable applied current densities, on a Pt surface region containing apparently some significant quantity of three-dimensionally sorbed H (136). 

Raney Ni particles become entrapped in the electrodeposited Ni under the influence of a cathodic current and stirring. The electrocatalytic behavior of this material was characterized by the Tafel parameters for H2 evolution for various quantities (mg cm" ) of the Raney particles deposited. Particle size and aging effects were also determined. Kinetic parameters for the HER on various coatings were determined and compared (181). A related process for binding and cementing electrocatalytic Ni powders used a three-dimensional aluminium phosphate polymer (182). The Ni active material developed in the form of spiky filaments. 

As the electrocatalytic behavior of Fe(III)TMPyP indicates, an increase in the concentration of the mediator leads to a corresponding increase in the net number of electrons transferred to dioxygen. Hence, sizable gains in electrocatalytic efficiency could, in principle, be achieved by immobilizing electrocatalysts on electrode surfaces, as will be discussed in detail in the next section. 

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