Photocatalytic Water Reduction with Copper‐Based Photosensitizers: A Noble‐Metal‐Free System

The provision of energy has been listed in the “Top Ten of global concerns” as the single most important issue to be faced to improve quality of life and ultimately to stop, or at least to mitigate, the environmental impact of human activities on the planet. [1] One way in which chemistry can be used to provide more sustainable and benign energy technologies is through the development of artificial photosynthesis systems, which allow for the conversion of the energy of sunlight into useful chemical energy by water splitting. [2] The resulting molecular hydrogen constitutes in principle a clean, renewable, and carbon-free energy source. [3]