Highly active bifunctional catalyst: Constructing FeWO₄-WO₃ heterostructure for water and hydrazine oxidation at large current density

Developing high performance anode catalysts for oxygen evolution reaction (OER) and hydrazine oxidation reaction (HzOR) at large current density is an efficient pathway to produce hydrogen. Herein, we synthesize a FeWO₄-WO₃ heterostructure catalyst growing on nickel foam (FeWO₄-WO₃/NF) by a combination of hydrothermal and calcination method. It shows good catalytic activity with ultralow potentials for OER (η₁₀ = 1.43 V, η_{1, 000} = 1.56 V) and HzOR (η₁₀ = −0.034 V, η_{1, 000} = 0.164 V). Moreover, there is little performance degradation after being tested for 100 h at 1, 000 (OER) and 100 (HzOR) mA·cm⁻², indicating good stability. The superior performance could be attributed to the wolframite structure and heterostructure: The former provides a high electrical conductivity to ensure the electronic transfer capability, and the later induces interfacial electron redistribution to enhance the intrinsic activity and stability. The work offers a brand-new way to prepare good performance catalysts for OER and HzOR, especially at large current density.