CO2 Hydrogenation to Formate and Methanol as an Alternative to Photo- and Electrochemical CO2 Reduction
Journal Papers
2015-12-09
CHEMICAL REVIEWS
SCIE、EI、PubMed、ESI高被引论文、ESI热点论文
J
115
23,SI
12936-12973
0009-2665
A study was conducted to show CO2hydrogenation as an alternative method for so-called artificial photosynthesis to produce fuels, such as formate/formic acid and methanol, with good selectivity and high efficiency. For CO2hydrogenation, an inexpensive and green source of H2is needed in contrast to the industrial reforming of natural gas. To obtain formic acid for the regeneration of H2or use in fuel cells, additional acid must be added to neutralize the formate. As an alternative to the use of a base in CO2hydrogenation, a Lewis acid is a useful additive for H2release from formic acid. To reduce the cost, catalysis with earth-abundant metals such as Fe or Co is highly desirable, and considerable progress has been achieved. Innovative ligands with functional groups are capable of gaining or losing one or more protons, and photoresponsive ligands capable of undergoing a useful change in properties upon irradiation. Kinetic isotope effects and computational studies provide clear evidence for the involvement of a water molecule in the rate-determining heterolysis of H2in CO2hydrogenation that accelerates proton transfer through the formation of a water bridge. Solution pH alters the rate-determining step for H2 generation from formic acid with these bioinspired complexes.