| dc.description.abstract | The development of efficient and stable electrocatalysts with low prices for the oxygen evolution reaction (OER) is pivotal in the advancement of water electrolyzer technologies for production of sustainable hydrogen fuel. High entropy ceramics have distinctive properties such as lattice distortion and high configurational entropy which can be very useful for catalytic purposes. In this work, through the application of the sol-gel auto-combustion method, five metal spinel containing 3d transition metals and Aluminum ((AlCrCoNiFe2)O) were prepared, and their electrocatalytic performance in comparison with other synthesized multi-metal and monometallic oxides for OER within an alkaline medium was analyzed. The electrochemical analysis revealed that the synthesized five metal spinel yielded the lowest charge transfer resistance (0.49 (Ω) at 1.666 V vs RHE ), Tafel slope (43 mV.dec-1), and overpotential (η10=320 mV) with nickel foam substrate outcomes mainly can be attributed to the space charge interfacial polarization stemming from defective crystal structure which can increase local electric field strength for metal-oxygen (M-O) bond breakage at reaction interface, mild covalency character of M-O bonds, fast charge transport and a small distance between active site. Totally all these factors can increase the rate of active sites formation, collision between intermediates, and O2 formation. High configurational entropy coming from the incorporation of five dissimilar metals into the crystal structure can also increase phase stability for OER. Kinetic modeling also can be a useful method for testifying possible reaction mechanism on the surface of multi-metal spinel.
Key words: Oxygen Evolution Reaction (OER), High Entropy Ceramics (HEC), Cocktail effect, Sol-gel auto-combustion method, Multimetallic spinel, Tafel slope, Overpotential, Space charge-interfacial polarization, Defective crystal structure, Local electric field strength, Metal-oxygen covalency, Charge transport, Active sites, Kinetic model, Reaction mechanism. | en_US |