Theoretical study of activation of O2 at cathode and CH3OH at anode of “CH3OH ‐O2” fuel cell using ZnC4H4 and CuC4H4 organometallic catalysts “a DFT study”

Abstract

AbstractStudying the interaction of oxygen molecule with organometallic compounds as low cost catalysts have always been an interesting research subject. So, in this study, the catalytic effect of TM‐C4H4 organometallic compounds (TM is Zn or Cu) was investigated to enhance the reaction rate of “methanol‐oxygen” fuel cell using density functional theory(DFT) calculations at the B3LYP level and the basis set of 6‐31G(d). In addition, the gap energy (Eg) for each of TM‐C4H4 and the adsorption energy(Ead) of each pair of TM‐C4H4/O2 and TM‐C4H4/CH3OH were calculated. Natural bond orbital (NBO) calculations were also performed to examine the charge transfer and bond stability. The results showed that, due to the adsorption process, the bond length of O=O increased about 16 and 20%, respectively, while the C and O distance in the CH3OH was increased by 137 and 199%, respectively. These rises are fairly due to the somewhat negative charge transfer from the organometallic compound to O2 or C–O in methanol. A bond elongation increases the chemical activity and reactivity of the reactants at the anode and the cathode of the studied fuel cell. The results showed that, ZnC4H4 activates O2 and CH3OH in the “CH3OH‐O2” fuel cell reaction more than the CuC4H4 compound.