The bromate–2‐aminophenol reaction in a batch reactor was investigated in this research, in which both simple and sequential oscillations were observed. The occurrence of sequential oscillations were found to be very sensitive to changes of the initial concentrations, where decreasing the concentration of sulfuric acid or sodium bromate or increasing the 2‐aminophenol concentration caused the two oscillation windows to coalesce. Lowering the reaction temperature from 30 to 5°C also caused the two oscillation windows to merge into one. A phase diagram in the bromate–sulfuric acid concentration plane demonstrates that sequential oscillations only occur within a narrow band of conditions. Mechanistic studies of the system through employing 1H NMR and mass spectrometry suggest that a dibrominated ortho‐benzoquinone is a major product. The oxidation of 2‐aminophenol, on the other hand, can lead to the formation of pyrocatechol, which may be the substrate responsible for the second set of oscillations.

The bromate–phenolsulfonate reaction was found to exhibit spontaneous oscillations in a batch reactor, where the addition of small amounts of ferroin would result in nonoscillatory behavior. As the ferroin concentration was increased, the system produced very rich nonlinear behavior, including three isolated oscillatory regimes that were separated by as long as 48 h nonoscillatory period. The long-lasting nonlinear behavior may be attributed to the slow desulfonation of phenolsulfonate in an acidic solution, forming phenol-like intermediates. However, unlike the bromate–phenol oscillator, oxygen was found to greatly influence the reaction, and various complex oscillations could be observed by tuning the oxygen concentration. Mechanistic studies performed through employing 1H NMR spectroscopy and mass spectrometry to measure intermediate species at different stages of the reaction were able to identify 1,4-benzoquinone, 2-bromo-1,4-benzoquinone, 2,6-dibromo-1,4-benzoquinone, and 2,4,6-tribromophenol as major components during the reaction.

Manifestation of the properties of 3,5-diaminobenzoic acid polymer film was explored by polymerizing 3,5-diaminobenzoic acid in the presence of bromate. Depending on the initial concentration of bromate, the 3,5diaminobenzoic acid solution was observed to transit from steady to oscillatory evolution in a batch reactor. The thus-fabricated film on Au electrodes exhibited different activities toward the electrochemical oxidation of pyrocatechol. The film synthesized at nonoscillatory conditions has a primary oxidation peak of pyrocatechol at about 0.20 V (vs Hg/Hg 2 SO 4 electrode), as opposed to 0.0 V with the film that was prepared under oscillatory conditions. A phase diagram in the bromate−sulfuric acid phase was constructed to demonstrate the influence of each parameter on the emergence of oscillatory behavior in the 3,5-diaminobenzoic acid system. Experiments showed that an increase in the concentrations of sulfuric acid and bromate greatly increased the frequency and reduced the induction period of these transient oscillations. Unlike the systems that used ortho-and para-disubstituted organic substrates, this 1,3,5-trisubstituted compound did not evolve through the dihydroxy intermediate (pyrocatechol/hydroquinone) as no peak for resorcinol (110 m/z) was found in any of the mass spectrometry results.

This research investigated responses of the Belousov–Zhabotinsky (BZ) reaction to the presence of a chemically inert Pt wire in solution. Experiments showed that connecting the Pt wire to a neutral ground caused a spontaneous drastic shift in the redox potential and might even induce complex behavior. Characterizations using an unstirred ferriin solution demonstrated the formation of a red colored propagating front at the grounded Pt wire, suggesting the reduction of ferriin to ferroin. Measurements with different combinations of electrodes in both stirred and reaction-diffusion media further confirmed the reduction of BZ metal catalysts at the Pt wire and the accompanying oxidation reaction at the reference electrode. The observed drastic change in redox potential and oscillation waveform can be understood based on the passive reduction reaction at the indicator electrode that is connected to the reference electrode through a potential meter. The obtained influence can be further manipulated by adding a resistor between the Pt wire and the neutral ground, making this convenient perturbation method attractive for the study of redox chemical reaction dynamics.

The Belousov−Zhabotinsky (BZ) oscillator was exploited in this study to manifest the formation of copper nanoparticles, which were synthesized through potentiostatic reduction of copper ions. The presence of copper ions in the BZ reaction led to the development of complex oscillations when the initial concentration of copper ions was increased to above a threshold level, in which period-doubled and mixed-mode oscillations were developed. Experiments showed that as a result of changing the BZ oscillator, copper deposits with different morphologies such as triangles, cubes, and tetrahedrons were formed. The potentiostatic reduction of copper ions also exhibited an oscillatory behavior with a frequency that was nearly the same as the BZ oscillations. The thus-fabricated copper deposit demonstrated great activity towards the electrochemical reduction of NO 3 − , in which the detection limit reached as low as 11.6 μM. Characterization with cyclic voltammetry indicates interactions between copper ions and the malonic acid substrate.