Density Functional Theory Study on the Interaction of O2 and H2O2 Molecules with the Active Sites of Cobalt–Polypyrrole Catalyst

Abstract

We investigate the interaction of O2 and H2O2 molecules with the active sites of cobalt–polypyrrole (Co–Ppy) catalyst using the density functional theory (DFT) calculations. Several configurations of Co–Nx clusters (x = 2, 3) are used to mimic the active sites structures of pyrolized Co–Ppy catalyst. The highest O–O bond elongation of the adsorbed O2 molecule on Co–Nx clusters is of about 17.14%. The O2 side-on adsorption configuration could be realized in the Co–N2 active sites that have bent N–Co–N angles and strong dxz/yz-orbitals characters in their frontier molecular orbitals (FMOs) and in the Co–N3–pyridinic–trimer active site that has no occupied dz2-like-orbital in its FMOs. Depending on the configuration of O2 adsorption on Co–Nx clusters and the amount of extra charges in anti-bonding orbitals (π*) of the adsorbed O2 molecule, the formed H2O2 molecule on Co–Nx clusters will be spontaneously dissociated into OH* molecules; otherwise it will be adsorbed in its molecular form.