The theory of the polarographic catalytic currents (mechanism CE) has been developed for the system: Ni2+-L-Xp- where L: pyridine (Py), nicotinamide (NA), N,N-diethylnicotinamide (DEN), nicotine (NC) and X p-: NO- 3, AcO-, HPO2- 4 . The theory is based on the kinetic parallel heterogeneous catalytic reactions: equation presented with the use of Langmuir's adsorbed isotherm. The kinetic equations obtained for average and instantaneous currents allowed to determine the Langmuir's parameters (NA<DEN<NC), kinetic parameters and the contribution of reactions 1a and b to the summary catalytic currents. The k″h value rises with the increase of the NiX 2-p stability constant. The correlation k″ h≤k″h was explained by the additional effect of the field electrode through Xp-. These effects base the reaction 1b instead of accepted early alternative reaction of the ligand exchange. In spite of the fact that k″h≤k″h, the contribution of the reaction 1a in the summary catalytic current attained more than 60% (Py, DEN) due to the influence of the ψ0 potential.
- Catalysis by pyridine and its derivatives
- Kinetic and adsorbed parameters
- Nickel (II) catalytic systems
- Parallel heterogeneous catalytic reactions
- Polarographic catalytic currents