Oxygen deficient layered double perovskite as an active cathode for CO2 electrolysis using a solid oxide conductor

Abstract

A-site ordered PrBaMn₂O_5+δ was investigated as a potential cathode for CO₂ electrolysis using a La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ (LSGM) electrolyte. The A-site ordered layered double perovskite, PrBaMn₂O_5+δ, was found to enhance electrocatalytic activity for CO₂ reduction on the cathode side since it supports mixed valent transition metal cations such as Mn, which could provide high electrical conductivity and maintain a large oxygen vacancy content, contributing to fast oxygen ion diffusion. It was found that during the oxidation of the reduced PrBaMn₂O_5+δ (O5 phase) to PrBaMn₂O_6−δ (O6 phase), a reversible oxygen switchover in the lattice takes place. In addition, here the successful CO₂ electrolysis was measured in LSGM electrolyte with this novel oxide electrode. It was found that this PrBaMn₂O_5+δ, layered perovskite cathode exhibits a performance with a current density of 0.85 A cm⁻² at 1.5 V and 850 °C and the electrochemical properties were also evaluated by impedance spectroscopy.