Switching between Two Oscillatory States Depending on the Electrical Potential

Various spatiotemporal patterns were created on the surface or in the body of cation-exchange resin beads which were loaded with the catalyst of the Belousov–Zhabotinsky (BZ) reaction. Either global oscillations (GO) or traveling waves (TW) and the switching between them were observed in the previous papers, but it was not clear how chemicals contribute to the reaction inside/around the BZ bead. In this paper, we scanned the electrical potential, E, from +1 to −1 V (negative scan) and then turned from −1 to +1 V (positive scan) to control the switching between GO and TW. We found that the electrical switching potential from TW to GO, E TG, and from GO to TW, E GT, depended on the scanning direction of E and the diameter of the bead, d. The present study suggests that the electrode-induced increase of the inhibitor, Br–, and the activator, HBrO2, around the BZ bead plays an important role in determining E TG and E GT.