Oxide electrocatalysts approach

XAS studies of, table, 34 276 Oxide electrocatalysts, 38 122-135 atom superposition and electron delocalization molecular orbital approach, 38 133-135... 

The poisoning influence of carbon monoxide diminishes as the temperature increases and at a 1 % and 2 % CO concentration, the hydrogen molecule oxidation rate approaches that of an unpoisoned platinum electrocatalyst at 200 °C. 

Three decades ago, Bockris et al. reported enhancement of the efficiency of methanol oxidation with a platinum-ruftienium alloy electrocatalyst. Two decades ago, another promising approach to electrocatalysis of methanol oxidation was presented. That was the platinum-ruthenium oxide electrocatalyst proposed by Watanabe and Motoo [24]. 

Electrocatalysts One can screen arrays for electrochemical activity using SECM. This rapid screening along with rapid array preparation is an excellent way to test very rapidly a large number of compositions. As described in Chapter 16, several different SECM modes can be employed. This approach has been used, for example, with oxygen reduction, water oxidation, and methanol oxidation electrocatalysts. 

Nano-electrode arrays can be formed through nano-structuring of the electrocatalyst on an inert electrode support. Indeed, if the current of the analyte reduction (oxidation) on a blank electrode is negligible compared to the activity of the electrocatalyst, the former can be considered as an insulator surface. Hence, for the synthesis of nanoelectrode arrays one has to carry out material nano-structuring. Recently, an elegant approach [140] for the electrosynthesis of mesoporous nano-structured surfaces by depositioning different metals (Pt, Pd, Co, Sn) through lyotropic liquid crystalline phases has been proposed [141-143],... 

Pt is, of course, not a good electrocatalyst for the O2 evolution reaction, although it is the best for the O2 reduction reaction. However, also with especially active oxides of extended surface area, the theoretical value of E° has never been observed. For this reason, the search for new or optimized materials is a scientific challenge but also an industrial need. A theoretical approach to O2 electrocatalysis can only be more empirical than in the case of hydrogen in view of the complexity of the mechanisms. However, a chemical concept that can be derived from scrutiny of the mechanisms mentioned above is that oxygen evolution on an oxide can be schematized as follows [59] ... 

A typical approach is to utilise a substrate which when hydrolysed by the enzyme gives rise to a product which can be easily detected elect-rochemically. Thiocholine can be easily detected using screen-printed carbon electrodes doped with cobalt phthalocyanine (CoPC) [18,19], which acts as an electrocatalyst for the oxidation of thiocholine at a lowered working potential of approximately +100 mV (vs. Ag/AgCl) [18,19], thereby minimising interference from other electroactive compounds ... 

In this section, we review approaches to predicting dissolution potentials in 6.1. Next we discuss the hydrogen evolution reaction and studies to understand it and predict new electrocatalysts in 6.2. Electrochemical oxidation reactions that are typical in fuel cells are discussed in 6.3. Finally, the studies on the increasingly important oxygen reduction reaction are reviewed in 6.4. 

An approach described most recently for maximizing CO tolerance at relatively low anode catalyst loadings involves a combination of a CO-tolerant electrocatalyst, for example, a PtRu alloy and a separate chemical oxidation catalyst layer of zero... 

The system was first applied for development of chemosensors for gaseous hydrogen chloride. Polyaniline, and its copolymers with different derivates of aniline were used. Then a similar approach was tested in the author s group for optimization of amperometric biosensors for glucose based on electrocatalytical detection of hydrogen peroxide. A pigment Prussian blue was used as an electrocatalyst for decomposition of this product of enzymatic oxidation of... 

Other approaches have focused upon using non-precious metals and their oxides as alternatives to the platinum catalysts. For example, the mixed oxide catalysts of the binary and ternary alloys of noble metals and transition metals have been investigated for the oxygen evolution reaction in solid polymer electrolyte water electrolyzers. Binary, ternary, and quaternary platinum alloys with base metals of Cu, Ni, and Co have been used as electrocatalysts in liquid acid electrolyte cells. It was also reported that a R-Cu-Cr alloy displayed better activity to oxygen reduction than R and Pt-Cr in liquid electrolyte.The enhanced electrocatalytic activity of these types of alloys has been attributed to various factors, including the decrease of the nearest neighbor distance of platinum,the formation of Raney type... 

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