Hydrogenation of CO2 into Formates by Ligand-Capped Palladium Heterogeneous Catalysts

The synthesis of two series of catalysts based on ligand-capped supported Pd nanoparticles was carried out using a simple procedure and the resulting materials were tested in the formate synthesis. Within these series, PPh3 revealed the most appropriate stabilizing ligand while TiO2 was the most efficient support for these catalysts. The hydrogenation of CO2 was carried out under mild reaction conditions (1.8 MPa CO2, 1.8 MPa H2, 60 °C) using water as solvent and in the presence of a base, providing excellent selectivity towards formates with a TON of 1032 (TOF of 69 h−1, [HCOOK]=1.1 mol/l).