Electrochemical desorption, reaction order

As mentioned in section 2.1, the results of photoelectrochemical experiments show that in the region of barrierless discharge of hydrogen ions at a mercury cathode, the HaO ions are the main proton donors for the electrochemical desorption reaction. Since in this case the reaction is first order with respect to hydrogen ions at a... 

CI2 evolution reaction, 38 56 electrochemical desorption, 38 53-54 electrode kinetics, 38 55-56 factors that determine, 38 55 ketone reduction, 38 56-57 Langmuir adsorption isotherm, 38 52 recombination desorption, 38 53 surface reaction-order factor, 38 52 Temkin and Frumkin isotherm, 38 53 real-area factor, 38 57-58 regular heterogeneous catalysis, 38 10-16 anodic oxidation of ammonia, 38 13 binding energy quantification, 38 15-16 Haber-Bosch atrunonia synthesis, 38 12-13... 

From the above it is seen how the same coverage functions, involving the lateral interaction factor g, determine both R and the Tafel slope values. In particular, for the electrochemical desorption mechanism, the Tafel slope b is found to be (RT/F)(—1 + whereas for the recombination-controlled mechanism it is simply (RT/F) , in terms of the reaction order, R. 

As far as the chl.e.r. mechanism is concerned, the same, previously described, investigation has been performed and Figures 24 and 25 respectively report the polarization curve and the Tafel plot (currents normalized to the number of active sites at the electrode surface), for the case of a 1 M NaCl/3 M NaC104/0.01 M HCIO4 test solution. The measured Tafel slope has a value of 0.149 V, and the reaction order with respect to CP is about 0.7 the values of b and R both agree well with a Volmer-Heyrovsky mechanism [24], with a rate-determining electrochemical desorption, provided a value of about 0.7 is assumed for the coverage by the intermediate chlorine radicals [28] ... 

For a low surface coverage, since the anodic reaction is first order with respect to chlorine this means that only one chloride ion participates in the slow stage and in all stages preceding it. This immediately allows us to disregard such mechanisms as slow recombination or slow electrochemical desorption, which require the reaction to be second order with respect to chloride (at a constant potential). ... 

Various mass spectroscopies are applicable ex situ in order to obtain molecular information. Secondary ion mass spectroscopy (SIMS) can be used [124, 125]. Thermal desorption mass spectroscopy is a viable alternative as a less intrusive and more surface sensitive tool [126, 127]. So far, the latter method has been applied exclusively to adsorbed hydrogen and carbon monoxide formed in an electrochemical reaction of organic CHO-compounds. 

The dismutation reaction (LXI) is rather surprising. Since the rate of the reverse of reaction (LXII) is negligible at substantial cathodic overpotentials (ry <0.1 V), reaction (LXI) is not just the simple electrochemical oxidation of the superoxide S-02 coupled with its further reduction. Further, it is unlikely that reaction (LXI) proceeds by the desorption of 2 followed by a second-order homogeneous reaction in the solution phase, i.e.. 

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