Electrochemical Investigations of Double Perovskite M2NiMnO6 (Where M = Eu, Gd, Tb) for High-Performance Oxygen Evolution Reaction

Double perovskites are known for their special structures which can be utilized as catalyst electrode materials for electrochemical water splitting to generate carbon-neutral hydrogen energy. In this work, we prepared lanthanide series metal-doped double perovskites at the M site such as M2NiMnO6 (where M = Eu, Gd, Tb) using the solid-state reaction method, and they were investigated for an oxygen evolution reaction (OER) study in an alkaline medium. It is revealed that the catalyst with a configuration of Tb2NiMnO6 has outstanding OER properties such as a low overpotential of 288 mV to achieve a current density of 10 mAcm(-2), a lower Tafel slope of 38.76 mVdec(-1), and a long cycling stability over 100 h of continuous operation. A-site doping causes an alteration in the oxidation or valence states of the NiMn cations, their porosity, and the oxygen vacancies. This is evidenced in terms of the Mn4+/Mn3+ ratio modifying electronic properties and the surface which facilitates the OER properties of the catalyst. This is discussed using electrochemical impedance spectroscopy (EIS) and electrochemical surface area (ECSA) of the catalysts. The proposed work is promising for the synthesis and utilization of future catalyst electrodes for high-performance electrochemical water splitting.

Automated summary

Double perovskites have been investigated as catalyst electrode materials for electrochemical water splitting. Metal-doped double perovskites were prepared and studied for oxygen evolution reaction (OER) in an alkaline medium. The results showed that a specific catalyst configuration exhibited excellent OER properties with low overpotential, low Tafel slope, and long cycling stability. A-site doping altered the electronic properties and surface structure of the catalyst, which enhanced its performance.