Interconversion of CO₂/H₂ and Formic Acid Under Mild Conditions in Water. Ligand Design for Effective Catalysis

Recent significant progress in the homogeneous catalytic hydrogenation of CO₂ to formate (the conjugate base of formic acid) and dehydrogenation of formic acid in various solvents including water is summarized. While formic acid is not the perfect H₂ storage solution, many researchers consider it better than other methods at this time because the interconversion of CO₂ and formic acid can take place cleanly to form H₂ without detectable CO under mild conditions. In this chapter, we explain how inspirations from biological systems guide us to design homogeneous transition-metal catalysts for carrying out the interconversion of CO₂ and formate under ambient conditions in environmentally benign and economically desirable water solvent.