Complexes in the Photocatalytic Reaction of CO 2 and H 2O: Theoretical Studies

Abstract

Complexes (H 2O/CO 2, e-(H 2O/CO 2) and h +-(H 2O/CO 2)) in the reaction system of CO 2 photoreduction with H 2O were researched by B3LYP and MP2 methods along with natural bond orbital (NBO) analysis. Geometries of these complexes were optimized and frequencies analysis performed. H 2O/CO 2 captured photo-induced electron and hole produced e-(H 2O/CO 2) and h +-(H 2O/CO 2), respectively. The results revealed that CO 2 and H 2O molecules could be activated by the photo-induced electrons and holes, and each of these complexes possessed two isomers. Due to the effect of photo-induced electrons, the bond length of C=O and H-O were lengthened, while H-O bonds were shortened, influenced by holes. The infrared (IR) adsorption frequencies of these complexes were different from that of CO 2 and H 2O, which might be attributed to the synergistic effect and which could not be captured experimentally. © 2010 by the authors; licensee MDPI, Basel, Switzerland.