Three-Dimensional Iron–Cobalt Bimetallic Dendrites on Gold Nanoparticles: A High-Performance Electrocatalyst for Oxygen Evolution Reaction

Electrochemical water splitting has recently gained significant attention due to the rising need for sustainable energy sources. Several electrocatalysts have been documented to overcome the challenges posed by the slow kinetics of the oxygen evolution reaction (OER). However, the majority of electrocatalysts are either expensive, have a larger overpotential, or need complicated multistep synthesis techniques, which restricts their wide applicability. Therefore, it is crucial to design catalysts with the aforementioned improved features. 3D metallic dendrites have gained significant attention as high-performance electrocatalysts for energy conversion, owing to their intricate hierarchical architecture resulting in abundant active sites. Iron nanostructures are known for their large surface area, conductivity, catalytic activity, high mechanical strength, increased electronic properties, and excellent chemical and thermal stability. Cobalt metal-based nanostructures are also known for their conductive and electronic properties. Moreover, gold nanoparticles (AuNPs) possess the ability to modulate the interfacial electrical characteristics of other catalysts and provide resistance to their dissolution. Taking all these aspects into consideration, bimetallic iron–cobalt nanodendrites (FeCo NDs) are designed on the conductive AuNPs-customized flexible electrode and subsequently employed for the OER in an alkaline solution. Electrochemical characterization analysis confirms that the OER electrocatalyst possesses approximately 66-fold lower resistance and 27-fold higher current response, thereby efficiently facilitating electron transfer. The electrocatalyst exhibited synergistically enhanced oxygen evolution activity, requiring only 139 mV overpotential at 10 mA cm–2 with a Tafel slope of 69.7 mV/dec, hence paving the way for more affordable water-splitting devices.