SHIFTING AND SWITCHING BETWEEN CHEMICAL STEADY-STATES THROUGH ELECTRODE PROCESSES

Transitions between two steady states in the bistability region of the Belousov-Zhabotinsky (BZ) reaction have been induced by the application of an electric current. The current causes redox processes which produce the perturbing species on Pt electrodes in two electrically coupled stirred flow reactors. One reactor is the anode while the other is the cathode, depending on the polarity of the applied current. On the thermodynamic branch outside the bistability region at low flow rates the steady state is shifted toward higher redox potentials in the anodic reactor proportional to the current flow. On the kinetic branch outside the bistability region at high flow rates the system is shifted by a threshold current to a lower steady state in the cathodic reactor. On both branches the system returns to its original steady states when the current is switched off, whereas in the bistability region the system remains on a given steady state.