Nonlinear Behavior of Nickel Dissolution in Sulfuric Acid in a Cathode-Anode Cell Configuration: Effect of Cathode Area

Abstract

We investigate the nonlinear behavior of anodic nickel dissolution reaction coupled to hydrogen ion reduction for different cathode sizes. In a standard three-electrode cell, transpassive nickel dissolution in sulfuric acid exhibits bistable and oscillating current states when an external resistance is added in series to the working electrode. We observed bistable and oscillating currents without any external resistance in a two-electrode (cathode-anode) cell. The oscillations are interpreted by the linear polarization resistance of the cathode reaction, hydrogen reduction on nickel surface; this resistance exhibited a maximum against cathode size. Those cathodes with resistances close to the maximum stimulated strong oscillations in the cell current. Theoretical considerations implied that such maximum differential resistance cannot be interpreted with elementary Butler-Volmer kinetics but require complex, multiroute reactions. Numerical model simulating coupled anode and cathode reactions reproduced the salient dynamical features of the cathode-anode cell configuration.

Nonlinear Dynamics of Coupled Nickel Electrodissolution with Hydrogen Ion Reduction with Bipolar Electrodes

“…While the total resistance with the traditional setup is nearly constant with increasing the potential, in the BPE the R ct depends on the current level. Previously, it was shown 25 that the effective R ct for a Butler-Volmer kinetics at large overpotentials is inversely proportional to the current level:…”

“…The type of the transition depended on the extent of nonlinearity of the oscillations: while relaxation oscillation exhibited regular quorum sensing (oscillations occurred with increasing population density), smooth oscillators demonstrated "inverse" quorum sensing (oscillations via decreased population density). In these results, [25][26][27] both cathode and anode reside in the same container and share common electrolyte.…”

“…In addition to oscillations, the BPE could also be used to study bistability when considering forward and backward scans in the LSV; here new factors should be considered, in particular, the current level affects the charge transfer resistance of the coupled electrode and thus the interpretation of the bistability ranges induced by saddle-node bifurcations should consider that the imposed charge transfer resistance depends on the current level. 25 The wireless feature of the BPE can open novel routes to studying nonlinear dynamics in electrochemistry; this feature is similar to coupling chemical reactions to obtain new types of behavior, as it was demonstrated with coupling of two reactors with the chlorite-iodide reaction for rhythmogenesis, 33 and the parallel coupled bromate-chlorite-idode system for birythmicity and compound oscillations. 34 Here we used a reference state where both compartments contained 3M H 2 SO 4 and changed the concentration in one of the compartments; future studies could explore the impact of antagonistic changes in both compartments, e.g., increasing the concentration in one compartment at the expense of decreasing the concentration in the other.…”

“…22 It is possible to produce desirable products simultaneously at both anode and cathode sides, which optimizes the energy efficiency. 23,24 The nonlinear dynamics of a coupled anode-cathode system, nickel electrodissultion and hydrogen ion reduction, was explored in a previous study 25 in a traditional two electrode system. Bistability and current oscillations were observed due to the interaction of the reactions.…”

Review—A Review on Electrodes Used in Electroorganic Synthesis and the Significance of Coupled Electrocatalytic Reactions

“…107 Despite the fact that nickel has shown similar proton reduction catalytic activity to that of Pt, due to its high dissolution rate and corresponding poor stability forbid its use in highly acidic environments such as H 2 SO 4 , HCl, HClO 4 etc. 108 At the same time, a mild organic acid such as pivalic acid was found to be an excellent catholyte (i.e. electrolytes in cathode compartment) for nickel electrode.…”