Solvothermally Synthesized Iron Phthalocyanine Nanostructure for High ORR Response: A Joint Experimental Investigation and DFT Analysis

Abstract

In search for replacement of expensive, rare platinum (Pt) based electrocatalyst towards oxygen reduction reaction (ORR), transition metal-cored phthalocyanine (MPc) have been under current research focus. Among various MPc, iron phthalocyanine (FePc) gives best ORR performance, presumably because of its strong electron withdrawing capability. Herein, we report one pot solvothermal synthesis of 1 Dimensional FePc nanostructure and its possible application as ORR catalyst. The ORR performance of FePc nanostructure was carried out in 0.1 M KOH (pH = 13) via cyclic voltammetry and linear sweep voltammetry. The performance, which was comparable with commercially available Pt/C, measures a half wave potential (E1/2 = 0.64 V vs RHE), onset potential (Eonset = 0.87 V vs RHE) and electron transfer number (n) of 3.9 at 0.35 V (vs RHE), indicating that the synthesized nanostructure essentially promote 4-electron reduction pathway. Additionally, unlike Pt/C, the synthesized nanostructure showed good methanol tolerance. To elucidate the ORR performance from FePc, first principle based DFT calculation on two dimensional FePc monolayer has been carried out and presented here for deeper insight. The excellent ORR activity coupled with methanol tolerance favors the FePc nanostructure as a promising alternative to conventional Pt-based electrocatalyst for future energy storage and fuel cells.