The photoinduced bifurcation structure in the Fe(CN)64--H2O2-H2SO 4 system in a continuous-flow stirred tank reactor has been determined. The photo-induced transition between the low-pH steady state and the oscillatory state shows a hysteresis, similarly to the dark reaction reported previously. The action spectrum for the photoinhibition of oscillations suggests that the primary light absorber in the visible region is Fe(CN)63-, similarly to the photoinduction of oscillations reported previously, while in the UV region Fe(CN)64- is also active. The primary photochemical processes are shown to be the following: Fe(CN)64- + H2O ⇄hv Fe(CN)5H2O3- + CN- and Fe(CN)63- + H2O ⇄hv Fe(CN)5H2O2- + CN-. The state diagram spanned by the irradiation light power and the flow rate as external control parameters is presented, on the basis of which the mechanism of oscillations is discussed qualitatively.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry