Scientific Achievement

A detailed stochastic kinetics simulation study of how solar excitation of a dye bound to catalyst drives water oxidation catalysis shows that progress through the catalytic cycle is not controlled by the low solar radiation flux or photoexcited charge carrier losses. It is gated by the buildup of intermediates whose chemical reactions are not controlled by dye excitations.

Significance and Impact

Dye-catalyst diads hold the promise of efficient charge management and chemical specificity for complex catalytic sequences, but how they work together is not well characterized. This study shows that solar excitation, charge transfers, and thermal reactions all control the timing of the catalytic cycle to varying degrees over timescales of ps to many minutes, and that the dye excitations and catalyst reactions are only loosely coordinated.

Research Details

  • Stochastic chemical kinetics simulations use Kinetiscope and generate an exact time base for comparison to experimental observations
  • Kinetics model constructed from full photophysics of the Ru dye in sunlight and from detailed water oxidation mechanistic information from the literature
  • Simulations performed for ensembles of diads (2×1010) for a light-dark sequence of 1200s-1200s and for single diads for light-dark sequences of 8hr-16hr (404 distinct simulations for statistical analysis)
  • Simulation results analyzed to trace catalytic intermediate populations across the cycle, and extract timings of excitations and reactions

Publication Details

Massad, R. Cheshire, T. P., Fan, C., Houle, F. A.*, Chemical Science, 2023, DOI: 10.1039/d2sc06966k

DOI: 10.1002/adma.202300542