Kinetics and mechanism pertaining to electroreduction of ammonia complexesof palladium(II) at the palladium electrode

Kinetics of electroreduction of complexes Pd(NH3)(4)(2+) is studied on the rotating palladium disk electrode in solutions containing different amounts of palladium complexes and ammonia at pH 5.8-12.8 in the presence of 0.1 M NaF. The study is conducted by obtaining steady-state cyclic voltammograms and pulsed galvanostatic and potentiostatic curves. Electroreduction of co mplexes Pd(NH3)(4)(2+) at pH 12.8 is hardly complicated by adsorption and a bsorption of hydrogen and includes a slow single-electron electrochemical s tage involving Pd(NH3)(4)(2+). The transfer coefficient and the rate consta nt of the cathodic process of electroreduction of complexes Pd(NH3)(4)(2+) on palladium are determined. It is shown that the process rate is independe nt of the structure of the electrical double layer, as opposed to that on t he mercury electrode. The complicating effect, exerted by adsorption and ab sorption of hydrogen on the process, is discussed. It is concluded that hyd rogen adsorbed on palladium hampers the process.