Bismuth electrode

Another possibility is to use bismuth-film-modified electrodes which were used, e.g., for detection of picric acid. Different types of bismuth-based electrodes (bismuth-film electrodes, bismuth bulk electrodes, bismuth-nanoparticle-modified electrodes) and their applications for determination of (among others) various nitrocompounds were reviewed. 

The best known of the M/Mfiy electrodes that are used for the determination of pH are the Sb/SbjOj electrodes, but metals such as bismuth and arsenic filmed with their respective oxide act in a similar manner. Copper in alkaline solutions appears to behave as a pH-dependent Cu/CujO,... 

Tetrabutylammonium [bismuth(III) bis(phthalocyanine)] undergoes a one-electron oxidation (dichloromethane, U = IV, platinum electrode, several days) to give bismuth bis(phthalocyanine).167... 

The electrochemical properties of bismuth solid drop electrodes have been studied extensively219,254,666-697 and several reviews74,153,219,254,670-672 have been published. 

The pc-Bi/aqueous solution interface has been studied mainly by Palm et a/.666-669 Ea= and other fundamental characteristics were obtained. The electrical double-layer structure at a bismuth solid drop electrode with remelted surface (BiDER/H20) was investigated by Salve... 

Arsenic and antimony are metalloids. They have been known in the pure state since ancient times because they are easily obtained from their ores (Fig. 15.3). In the elemental state, they are used primarily in the semiconductor industry and in the lead alloys used as electrodes in storage batteries. Gallium arsenide is used in lasers, including the lasers used in CD players. Metallic bismuth, with its large, weakly bonded atoms, has a low melting point and is used in alloys that serve as fire detectors in sprinkler systems the alloy melts when a fire breaks out nearby, and the sprinkler system is activated. Like ice, solid bismuth is less dense than the liquid. As a result, molten bismuth does not shrink when it solidifies in molds, and so it is used to make low-temperature castings. 

The properties of anodic layers of HgS formed on mercury in sulfide solutions have been investigated in comparison with anodic sulfide layers of cadmium and bismuth. Also, the electrochemistry of mercury electrodes in aqueous selenite solutions has been studied (see Sect. 3.2.1). The problem with the presence of several cathodic stripping peaks for HgSe in acidic Se(IV) solutions has been addressed using various voltammetric techniques at a hanging-mercury-drop electrode [119]. 

In their pioneering work on the formation of photoelectrochemically active metal sulfides by oxidation of the parent metal electrode. Miller and Heller [29] reported the anodic formation of polycrystalline Bi2S3 on a bismuth metal electrode in a sodium polysulfide cell, wherein this electrode was used in situ as photoanode. When a Bi metal electrode is anodized in aqueous sulfide solutions a surface film is formed by the reaction... 

MiUer B, Menezes S, Heller A (1978) Anodic formation of semiconductive sulfide films at cadmium and bismuth Rotating ring-disk electrode studies. 1 Electroanal Chem 94 85-97... 

An interesting idea has been to prepare the photosensitive electrode on site having the liquid play the dual role of a medium for anodic film growth on a metal electrode and a potential-determining redox electrolyte in the electrochemical solar cell. Such integration of the preparation process with PEC realization was demonstrated initially by Miller and Heller [86], who showed that photosensitive sulfide layers could be grown on bismuth and cadmium electrodes in solutions of sodium polysulfide and then used in situ as photoanodes driving the... 

Another important difference in the poison formation reaction is observed when studying this reaction on Pt(lll) electrodes covered with different adatoms. On Pt(lll) electrodes covered with bismuth, the formation of CO ceased at relatively high coverages only when isolated Pt sites were found on the surface [Herrero et al., 1993]. For formic acid, the formation takes place only at defects thus, small bismuth coverages are able to stop poison formation [Herrero et al., 1993 Macia et al., 1999]. Thus, an ideal Pt(lll) electrode would form CO from methanol but not from formic acid. This important difference indicates that the mechanism proposed in (6.17) is not vahd. It should be noted that the most difhcult step in the oxidation mechanism of methanol is probably the addition of the oxygen atom required to yield CO2. In the case of formic acid, this step is not necessary, since the molecule has already two oxygen atoms. For that reason, the adatoms that enhance formic acid oxidation, such as bismuth or palladium, do not show any catalytic effect for methanol oxidation. 

Henero E, Femandez-Vega A, Feliu JM, Aldaz A. 1993. Poison formation reaction from formic acid and methanol on platinum (111) electrodes modified by irreversibly adsorbed bismuth and arsenic. J Electroanal Chem 350 73-88. 

Macia MD, Herrero E, Fehu JM, Aldaz A. 1999. Fomtic acid self-poisoning on bismuth-modified Pt(755) and Pt(775) electrodes. Electrochem Commun 1 87-89. 

Smith PE, Ben-Dor KF, Abruna HD. 2000. Poison formation upon the dissociative adsorption of formic acid on bismuth-modified stepped platinum electrodes. Langmuir 16 787-794. 

Figure 7.6 Bismuth deposition on a Pt(775) electrode from 5 pM Bi + 0.5 M H2SO4 solution. The results have been divided into two graphs for the sake of clarity. Sweep rate 50mV/s.

Clavilier J, Feliu JM, Aldaz A. 1988. An irreversible structure sensitive adsorption step in bismuth underpotential deposition at platinum electrodes. J Electroanal Chem 243 419-433. 

Climent V, Herrero E, Eeliu JM. 2001. Positive shift of the potential of zero total charge of stepped Pt(lll) electrodes decorated by irreversibly adsorbed bismuth. Electrochem Comm 3 590-594. 

Climent V, Garcia-Araez N, Compton RG, Feliu JM. 2006. Effect of deposited bismuth on the potential of maximum entropy of Pt(lll) single-crystal electrodes. J Phys Chem B 110 21092-21100. 

Hamm UW, Kramer D, Zhai RS, Kolb DM. 1998. On the valence state of bismuth adsorbed on a Pt(lll) electrode—An electrochemistry, LEED and XPS study. Electrochim Acta 43 2969-2978. 

Herteto E, FeUu JM, Aldaz A. 1995a. CO adsorption and oxidation on Pt(l 11) electrodes modified by irreversibly adsorbed bismuth in sulfuric acid medium. J Catal 152 264-274. 

Smith SPE, Ahruna HD. 1999a. Structural effects on the oxidation of HCOOH by bismuth modified Pt(lll) electrodes with (110) monatomic steps. J Electroanal Chem 467 43-49. 

Smith SPE, Ahruna HD. 1999h. The coadsorption of UPD copper and irreversibly adsorbed bismuth on Pt(lll) and Pt(lOO) electrodes. J Phys Chem B 103 6764-6769. 

Metal oxide electrodes are also of the second type. A well known example is a rod of antimony coated with Sb203 (or bismuth with Bi203), which can function as a pH electrode33 ... 

Many other heterogeneous electrodes have been developed based on, e.g., calcium oxalate or stearate in paraffin, barium sulphate in paraffin or silicone-rubber, bismuth phosphate or iron(III) phosphate in silicone-rubber, caesium dodecamolybdophosphate in silicone-rubber and amminenickel nitrate in phenol-formaldehyde resin39 these permit the determination, respectively, of Ca and oxalate, Ba and sulphate, Bi or Fe(HI) and phosphate, Cs, Ni and nitrate, etc. 

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