Electrocatalytic properties of perovskite-type La1-xSrxMnO3 obtained by a novel sol-gel route for O2 evolution in KOH solutions

Abstract

Perovskite-type La1-xSrxMnO3 were synthesized at 600°C by a sol-gel route involving polyacrylic acid as precursor and investigated as electrocatalysts for the O2-evolution reaction (OER) in KOH solutions. The oxide powders were produced in the form of films on pretreated Ni-supports by an oxide-slurry painting technique. The study showed that Sr-substitution in the oxide matrix did not influence the oxide roughness significantly. The true electrocatalytic activity of the catalyst decreased with increasing Sr-substitution. The reaction order has been found to be approximately unity in OH- concentration. The Tafel slope values at low potential ranged between ∼ 103 and ∼ 116 mV decade-1. The rate of OE increased with increasing temperature following the Arrhenius law. Sr-substitution of 0.4 mol reduced the electrochemical activation energy (ΔHel#0) for OE by 12.9 kJ mol-1. © 2002 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.