Abstract
A modified version of the short-lived BrO3−–H2PO2−–Mn(II)–N2 oscillator, the BrO3−–H2PO2−–acetone–dual catalyst system, where the catalyst pair can be Mn(II)–Ru(bpy)3SO4, or Mn(II)–ferroin, or Mn(II)–diphenylamine, shows long-lasting batch oscillations in the potential of a Pt electrode and in colour, accompanying periodic transitions between the oxidised and reduced forms of the catalysts. Experimental conditions for the oscillations are established. The origin of the batch oscillations and the role of the catalyst pair in the oscillatory behaviour are discussed. The new system is ideally suited to the study of waves and patterns in reaction–diffusion systems, since in addition to the longevity of its spatial behaviour in batch, it produces no gaseous or solid products and exhibits significant photosensitivity.