Synthesis Methods for Electrochemically Applicable High Entropy Oxides

As field-dispatchable power sources offer an alternative means of energy conversion, electrocatalyst development has become an area of intense focus. Emphasis has been placed on the transition from expensive electrocatalysts such as platinum and palladium toward earth abundant materials. Such a shift would result in lowered costs, enhanced durability, and an increased potential for implementation on a broader scale. High entropy oxides (HEOs) are an emerging class of materials that can offer both earth abundance and tunability of composition and morphology, making them excellent candidates for electrocatalysis. Several approaches have been taken to synthesize these materials and achieve balance between single-phase, highly crystalline products and high-surface area, nanostructured products. This work offers a survey of these methods, as well as our perspective on the most promising pathways forward. Emphasis is placed on clarifying the benefits, challenges, and overall suitability of each means of synthesis with electrocatalytic applications in mind.