ELECTRICAL PULSES TO DETERMINE CHEMICAL-PHASE RESPONSE CURVES

We report several series of single perturbation experiments in the Bel ousov-Zhabotinsky (BZ) reaction which have been carried out by applyin g an electrical current to a platinum electrode in the continuous flow stirred tank reactor (6.4 mL). When a single short current pulse is a pplied at the maximum of a chemical oscillation (high Ce4+ concentrati on) or at the minimum (low Ce4+), the response is a small advance or a significant delay of the original phase of oscillation (negative or p ositive phase shift), respectively. Thus we obtain phase response curv es as a function of electrical current strength and duration of the pu lses. These results show that the redox reactions occurring at the pla tinum electrodes involve mainly the Ce3+/Ce4+ redox couple as supporte d by pulsed additions of known Ce4+ solutions. Numerical simulations a re in good agreement with the experiments.