Low-Temperature Crystallization of Lafeo3 and Inherent Surface Activation for Efficient Oxygen Evolution Reaction Catalysts

This study reports a facile and economic method for LaFeO 3 perovskite crystallization process at low temperature range from 300 o C to 500 o C and an outstanding oxygen evolution reaction (OER) catalyst based on inherent catalytically surface. As a key material for low temperature synthesis, cyanogel-peroxo-complex as a metastable molecular precursor was synthesized via ligand exchange using potassium cyanide solution to provide superoxo (O 2 – ) ligand to Fe-CN-La gel structure, leading to a high degree of crystallinity with ideal ABO 3 stoichiometry at low temperatures (400 ~ 500 o C). Electrocatalysts based on LaFeO 3 nanoparticles were fabricated, showing an outstanding OER performance with low overpotential of ~ 438 mV at 100 mA/cm 2 and small Tafel slope of 61 mV×dec –1 under alkaline conditions, better than commercialized available IrO x /C catalysts. Its OER performance is attributed to the inherent oxygen-deficient layer at the surface created at low temperature (300 o C). Long-term stability test shows no significant change (< 1%) in the potential during 50 h, indicating a high stability of such catalysts.