Direct platinization

Similar size effects have been observed in some other electrochemical systems, but by far not in all of them. At platinized platinum, the rate of hydrogen ionization and evolution is approximately an order of magnitude lower than at smooth platinum. Yet in the literature, examples can be found where such a size effect is absent or where it is in the opposite direction. In cathodic oxygen reduction at platinum and at silver, there is little difference in the reaction rates between smooth and disperse electrodes. In methanol oxidation at nickel electrodes in alkaline solution, the reaction rate increases markedly with increasing degree of dispersion of the nickel powders. Such size effects have been reported in many papers and were the subject of reviews (Kinoshita, 1982 Mukerjee, 1990). 

Dubau L. 2002. Electrocatalyseurs platine-mthenium nanodisperses pour une pile a combustion directe de methanol. PhD Thesis, University of Poitiers, Prance. 

Shukla A, Neergat M, Parthasarathi B, Jayaram V, Hegde MS. 2001. An XPS study on binary and ternary alloys of transition metals with platinized carbon and its bearing upon oxygen electroreduction in direct methanol fuel cells. J Electroanal Chem 504 111-119. 

Y. Lee, J. Yang, S.M. Rudich, R.J. Schreiner, and M.E. Meyerhoff, Improved planar amperometric nitric oxide sensor based on platinized platinum anode. 2. Direct real-time measurement of NO generated from porcine kidney slices in the presence of L-arginine, L-arginine polymers, and protamine. Anal. Chem. 76,545-551 (2004). 

The following procedures describe the direct preparations of fttzns-[PtCl2 P(C6H5)3 2] and trans-[PtClj [P(n-C4H9)3] 2] by the reaction between the appropriate tertiary phosphine and potassium trichlorofethylene)-platinate(II) ... 

The nitrate, [Pt(NH3)4I2](N03)a, is produced in the same manner by the direct addition of iodine to tetrammino-platinous nitrate. It is soluble in hot water, and silver nitrate in boiling solution transforms the compound into nitrato-hydroxo-platinic nitrate. 

Both the dry complex oxalate and its aqueous solution are unstable to direct light and deposit yellow ferrous oxalate. This property was formerly utilized in platinotypes—a photographic process by which the FeCaO produced by illumination reduces a platinic salt to a black platinum image. The oxalate is a mixture, which has been resolved into its mirror images. 

A characteristic feature of these partially oxidized bis(oxalato)platinate salts of divalent cations is the coexistence of two modulations of the lattice over a wide temperature range (a) a one-dimensional modulation, as detected by the appearance of diffuse lines on X-ray films, perpendicular to the [Pt(C204)2] anion stacking direction and surrounding the even Bragg reflection layer lines of non-zero order (b) a three-dimensional modulation which gives rise to a complicated pattern of fine satellite spots in the neighbourhood of every reciprocal layer line. 

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