Electronic Properties of selected Metallophthalocyanines of iron using computational methods for ORR catalysis
                                             PalesaPhooko^1,2,3*, GetachewAdam Workneh^2,3*, SirayeEsubalew^2,3, AselefechSorsa^{2,3
                                             1}Department of Chemistry, National University of Lesotho, P.O. Roma 180, Lesotho
                                            ²Department of industrial Chemistry, Addis Ababa Science and Technology University, P.O. Box 16417, Addis Ababa , Ethiopia
                                            ³Sustainable Energy Center of Excellence, Addis Ababa Science and Technology University, P.O. Box 16417, Addis Ababa, Ethiopia
                                                    *Corresponding Authors: palesa.mathese@aastu.edu.et,  getachew.adam@aastu.edu.et

 

The ORR at the cathode is particularly challenging as it involves a complex four (4) electron transfer mechanism. As a result, the ORR kinetics is very slow and highly irreversible.  Thus, highly efficient ORR electrocatalysts are needed to drive the fuel cells. The density functional theory at the B3LYP level using LANL2DZ basis set was used for the investigation of electronic properties of the selected iron phthalocyanines as the potential electrocatalysts for oxygen reduction reaction (ORR). The electronic properties and chemical activity of the titled compounds were investigated by means of several theoretical approaches including geometry optimization, excited states and UV-Vis, molecular electrostatic potential surface, natural bond orbital, and frontier molecular orbital analyses. It was established that the use of electron donor substituents like the ethoxy group and DMSO for push up effect might boost the catalytic behavior of iron phthalocyanines. This was based on the stability, shorter Fe-N bond lengths, the HOMO-LUMO gaps and the band gap analysis. It was established that the use of nitro substituent and pyridine for push up effect might boost the catalytic behavior of iron phthalocyanines and this could be due to their electron withdrawing behavior. Since the positive regions are localized on the Fe2+ site, which can be considered as possible sites for nucleophilic attack. Both NBO analysis  and fukui function  revealed that the Fe site is more electron deficient with the electron withdrawing substituents and electron donating axial ligands or bridging  groups in a case of bimetallic systems.