Heterogeneous interfacial engineering of 3D hierarchical Ni3Se4/FeSe@N-doped carbon nanoflower enabling enhanced oxygen evolution reaction

The pursuit of efficient, durable, and cost-effective oxygen evolution reaction (OER) electrocatalysts is of great significance for advancing sustainable energy technologies. Herein, a three-dimensional hierarchical N-doped carbon nanoflower encapsulated with nickel iron selenide (Ni 3 Se 4 /FeSe HNCNF) was fabricated via selenization of the iron salts decorated nickel coordination polymers. The obtained Ni 3 Se 4 /FeSe HNCNF presents abundant heterogenous interfaces, which effectively optimize the electronic configuration, substantially expediting charge-transfer kinetics. Additionally, the hierarchical nanoflower-like N-doped carbon framework maximizes the exposure of catalytic sites and restrains nanoparticle accumulation and erosion. Benefiting from these structural and compositional advantages, Ni 3 Se 4 /FeSe HNCNF delivers remarkable OER performance in alkaline medium (1.0   M KOH), achieving a low overpotential of 280   mV at 10   mA   cm -2 , along with excellent durability exceeding 27   h at 10   mA   cm -2 and 100   mA   cm -2 . This study highlights the potential of heterostructure engineering and three-dimensional hierarchical design in bimetallic selenides, offering new insights into the development of next-generation high-performance OER electrocatalysts.