Sustainable visible light assisted in situ hydrogenation via a magnesium-water system catalyzed by a Pd-g-C₃N₄ photocatalyst

A non-hazardous and relatively mild protocol was formulated for an effectual hydrogen generation process via a "magnesium-activated water" system with a Pd-g-C₃N₄ photocatalyst under visible light at room temperature. Water functions photochemically as a hydrogen donor without any external source with the Pd-g-C₃N₄ photocatalyst. The synthesized Pd-g-C₃N₄ photocatalyst is highly efficient under visible light for the selective reduction of a wide range of unsaturated derivatives and nitro compounds to afford excellent yields (>99%). The photocatalyst Pd-g-C₃N₄ could be easily recovered and reused for several runs without any deactivation during the photochemical hydrogen transfer reaction process.