Hollow Iron–Vanadium Composite Spheres: A Highly Efficient Iron‐Based Water Oxidation Electrocatalyst without the Need for Nickel or Cobalt

Noble‐metal‐free bimetal‐based electrocatalysts have shown high efficiency for water oxidation. Ni and/or Co in these electrocatalysts are essential to provide a conductive, high‐surface area and a chemically stable host. However, the necessity of Ni or Co limits the scope of low‐cost electrocatalysts. Herein, we report a hierarchical hollow FeV composite, which is Ni‐ and Co‐free and highly efficient for electrocatalytic water oxidation with low overpotential 390 mV (10 mA cm−2 catalytic current density), low Tafel slope of 36.7 mV dec−1, and a considerable durability. This work provides a novel and efficient catalyst, and greatly expands the scope of low‐cost Fe‐based electrocatalysts for water splitting without need of Ni or Co. Missing, but not missed: Vanadium‐doped FeOOH is a low‐cost, highly efficient iron‐based electrocatalyst for water oxidation without Ni or Co participation. It exhibits a low overpotential 390 mV (10 mA cm−2 catalytic current density), low Tafel slope of 36.7 mV dec−1, and a considerable durability.