Low-temperature crystallization of LaFeO3 perovskite with inherent catalytically surface for the enhanced oxygen evolution reaction

Abstract

This study reports a facile and economic method for LaFeO3 perovskite crystallization process at low temperature range from 300 °C to 500 °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 (O2–) ligand to Fe-CN-La gel structure, leading to a high degree of crystallinity with ideal ABO3 stoichiometry at low temperatures (400 ∼ 500 °C). Electrocatalysts based on LaFeO3 nanoparticles were fabricated, showing an outstanding OER performance with low overpotential of ∼ 438 mV at 100 mA/cm2 and small Tafel slope of 61 mV·dec–1 under alkaline conditions, better than commercialized available IrOx/C catalysts. Its OER performance is attributed to the inherent oxygen-deficient layer at the surface created at low temperature (300 °C). Long-term stability test shows no significant change (< 1%) in the potential during 50 h, indicating a high stability of such catalysts.