Elevating Oxygen Evolution using Iron Phthalocyanine Infused Vanillic acid Electrocatalyst

Oxygen evolution reaction (OER) is the bottle neck step in water splitting reaction towards the realization of hydrogen based clean energy production and storage. Metal air batteries and polymer electrolyte membrane fuel cells (PEMFC) are the alternative green energy systems that utilise O₂ and H₂ in the production of continuous and high energy output without the utilization of carbon based fuels which are the major sources of pollution. Transition metal based N₄ organics are explored extensively as oxygen electrocatalysts i. e., OER and oxygen reduction reaction (ORR) catalysts because of their ease of synthesis, tuneable properties, low cost and high performance with long term stability. Here, vanillic acid functionalized iron phthalocyanine (FeVAPc) was synthesised and characterised by various spectroscopic techniques. The novel FeVAPc exhibited good thermal stability and was coated on Ni foam for OER studies. The scanning electron microscopy images showed net-work like surface morphology and the X-ray photoelectron spectroscopy indicated the presence of Fe in +3 oxidation state. The Ni/FeVAPc demonstrated excellent electrocatalytic activity for OER with overpotential of 312 mV at 10 mA.cm^-2 current density in 1.0 M KOH electrolyte. The designed organic based catalyst exhibited lesser Tafel slope value which is nearer to the benchmark catalyst, IrO₂. The proposed catalyst exhibited good stability as phthalocyanines are highly stable and do not undergo decomposition even in strong acidic and basic corrosive media. Integration of FeVAPc onto the Ni foam resulted in higher mass activity, lower charge transfer resistance, high active surface area leading to enhanced conductivity and activity. The fabricated Ni/FeVAPc is an appropriate cost-effective, efficient and stable catalyst for OER towards industrial applications.