Construction of hierarchical Ni-MoO2/WO2 heterostructure as self-supported electrode for superior alkaline hydrogen evolution reaction

The construction of heterogeneous interface is considered as an efficient approach to improve the intrinsic catalytic activity of hydrogen evolution electrocatalysts. Here, a self-supported heterostructured electrocatalyst (Ni-MoO 2 /WO 2 ) is fabricated by anchoring porous Ni-MoO 2 /WO 2 nanoflakes with a densely intermediate layer of Ni-MoO 2 /WO 2 nanoparticles on Ni foam through a three-step procedure involving corrosion, hydrothermal and annealing treatment. The Ni-MoO 2 /WO 2 heterostructure can modulate the interfacial electronic state and accelerate the reaction kinetics. The middle layer tightly anchors the catalytic layer to the substrate, preventing the detachment of the catalyst under high current density. The Ni-MoO 2 /WO 2 electrode exhibits a low overpotential of 30 mV at 10 mA cm −2 , a small Tafel slope of 63 mV dec −1 and excellent catalytic stability at 50 mA cm −2 beyond 50 h toward the hydrogen evolution reaction in alkaline solution. This work presents a new strategy to develop non-precious electrocatalysts with high performance for alkaline HER.