Pd supported on g-C3N4 nanosheets: Mott–Schottky heterojunction catalyst for transfer hydrogenation of nitroarenes using formic acid as hydrogen source

Well-dispersed Pd nanoparticles were anchored on g-C3N4 nanosheets, which were prepared by a liquid-phase exfoliation method. The hybrid material displayed excellent catalytic activity for the transfer hydrogenation of nitroarenes. The reactions can be conducted smoothly in water at room temperature with formic acid as hydrogen source. Aniline was produced in excellent yield (>99%; turnover frequency: 853), surpassing the majority of reported heterogeneous catalysts using formic acid or formates as hydrogen source. The increased activity of such a hybrid catalyst can be ascribed to the nitrogen-rich and amphipathic property of the carbon nitride support, the stable and uniform dispersed Pd nanoparticles and the Mott–Schottky effect between the g-C3N4 nanosheets and the metal nanoparticles. The heterogeneous Mott–Schottky catalyst can be reused for five cycles without any obvious loss of its catalytic activity.