Marcus Theory of Electron Transfer -- Photosynthetic Reaction Center Models -- Electron Donor-Acceptor Dyads -- Supramolecular Electron Transfer -- Effects of Metal Ions on Photoinduced Electron Transfer -- Photoredox Catalysis -- Hydrogen Storage -- Metal Ion-Coupled Electron Transfer (MCET) -- Catalytic Reduction of O2 -- Catalytic Oxidation of H2O -- Production of Hydrogen Peroxide from Water and Oxygen as a Solar Fuel -- Production and Usage of Hydrogen Peroxide as a Solar Fuel in Seawater -- Photosystem II Mimic -- Conclusion and Perspective.