Electrochemical insights into layered La2CuO4 perovskite: active ionic copper for selective CO2 electroreduction at low overpotential

Abstract

La2CuO4, a layered perovskites oxide was synthesized using solution combustion method at different calcination temperatures. XRD characterization and Rietveld refinement analysis confirms the pure phase of the synthesized material. The effect of calcination causes shrinking in the lattice parameters affirm the change in the oxygen stoichiometry. Four Probe (Van der Pauw�s) and CP-AFM analysis were carried out to understand the influences of calcination temperature on electrical conductivity. Electrochemical investigations on La2CuO4 were performed at various negative potential ranges using cyclic voltammetry (CV) to identify the redox active centre. Thermodynamic calculations are further carried out to validate the electrochemical results in different mediums. Selective electrocatalytic conversion of CO2 to C2-hydrocarbon (C2H4) with FE% of 40.3% which is 10 times higher than CH4 (FE%?=?4.1%) emphasized the in-situ formation of Cu2O from the redox active centre present in La2CuO4. Hydrocarbons are generated at a very low overvoltage (?0.4?V RHE) in comparison to literature. XPS analysis indeed confirms the presence of Cu+ species i.e., in-situ generated Cu2O, on La2CuO4 after CV and CO2 electrocatalysis.