Harnessing Native Iron Ore as an Efficient Electrocatalyst for Overall Water Splitting

Electrochemical water splitting is a widely accepted approach to generate hydrogen at a scale that is suitable for storing renewable energy. Therefore, the choice of catalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are critical in terms of cost when scaling up this technology. Thus, earth abundant transition metals oxides and sulfides have received significant attention as catalysts for the OER and HER, respectively. However, very few examples of actual Earth abundant materials mined from the Earth's crust have been used as electrocatalysts for these reactions. Here, we demonstrate that a raw iron ore is active for both the HER and OER under alkaline conditions, which is due to the natural abundance of the key elements of iron, nickel, and sulfur. The catalyst is stable for both reactions and can operate at 100 mA cm⁻², which is comparable to many chemically synthesised nanomaterials based on these elements. This approach may be attractive for adding value to iron ore while minimising the cost of catalyst production.