Maghemite Nanospheres on Nickel Foam as an Electrocatalyst for Water Splitting

Overview

Hydrogen has shown promise as the future of zero-carbon energy storage. However, partly due to the cost of noble metal electrocatalysts for Alkaline Water Splitting (AWS), most hydrogen production continues to rely on fossil fuels. Given these considerations, this work demonstrates the synthesis of an inexpensive, novel maghemite nanosphere electrode. The electrocatalyst was prepared via a newly devised process involving the aerobic conversion of an iron hydroxide precursor using the modified Shikorr reaction and oxidation of a magnetite intermediate, resulting in the agglomeration of inverse spinel cubic structures, forming nanospheres. The electrode presented excellent electrocatalytic activities in a KOH medium with low overpotentials, outperforming the standard RuO2 noble metal electrode at high current densities in the Oxygen Evolution Reaction (OER) due to the effect of cation vacancies on anion intermediate binding energy. The electrochemically active surface area (ECSA) of the electrocatalyst was increased by 274% and 335% for the Hydrogen Evolution Reaction (HER) and the OER, respectively, reducing the bubble problem and thus dramatically increasing efficiency. Furthermore, the synthesized electrocatalyst demonstrated better stability over 120 hours than the noble metal catalysts RuO2 and Pt. Overall, this solvothermal method exhibits potential to be generalized to the synthesis of other transition metal oxide-based nanostructures for a wide variety of material applications. Similarly, the discovered pathway to produce magnetite from iron hydroxide in an aerobic environment has numerous applications in biomedical nanotechnology.

Competition history

• AJAS 2024 Category not listed

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