The critical role played by the catalytic moiety in the early-time photodynamics of hydrogen generating bimetallic photocatalysts(full pdf)
Qing Pan, Francesco Mecozzi, Jeroen P. Korterik, Johannes G. Vos, Wesley R. Browne, Annemarie Huijser
10.1002/cphc.201600458 accepted june 3, 2016
The effect of the catalytic moiety on the early-time photodynamics of Ru/M (M = Pt or Pd) bimetallic photocatalysts is studied by ultrafast transient absorption spectroscopy. In comparison to the Ru/Pd photocatalyst described earlier, the Ru/Pt analogue showed complex excited state dynamics with three distinct kinetic components ranging from sub-ps to 102 ps, requiring a more sophisticated photophysical model than that developed earlier forthe Ru/Pd complex. In the Pu/Pt complex an additional lower-lying excited state is proposed to quench the hot higher-lying tripletmetal-to-ligand charge transfer states. Furthermore, a strong excitation wavelength dependence on the population of excited states is observed for both the Ru/Pt and Ru/Pd complexes, indicating a non-equilibrated distribution even on the 102 ps timescale. These insights shed light on the significant impact of the catalytic moiety on the fundamental early-time photophysics of Ru-based photocatalysts.