Simulated Dynamics of Photochemical Water Splitting

Abstract

The evolution of a photochemical water splitting system under continuous irradiation is analysed by numerical simulation for various kinetic and thermodynamic conditions, up to atmospheric pressures of H₂ and O₂. The analysis shows that it will often be very difficult to interpret experimentally the effect of one variable on the evolution of the system owing to variations in the latency period and the time at which the system reaches a photostationary state. Furthermore, the standard components of sacrificial systems, such as the sensitizer Ru ( bpy )₃²⁺ and the electron acceptor methyl viologen , are found to be very ill-suited for a complete photoconversion system. The key problem of poor performance is the fact that intermediate species generated by the system become majority species. These broad conclusions are quantified by our simulations and the benefits and drawbacks of various optimization procedures are presented.