Interface regulable NiFePBA/Fe2NiSe4 heterostructure for efficient electrocatalytic oxygen evolution reaction

The oxygen evolution reaction (OER) confronts significant challenges due to its intricate electron transfer mechanism, which leads to slow reaction kinetics and high energy barriers. Traditional catalysts possess drawbacks of cost and scarcity, limiting their applicability on a large scale. In this study, we developed a heterojunction catalyst via a hydrothermal method, in situ growing Fe 2 NiSe 4 on the surface of NiFePBA (NiFePBA/Fe 2 NiSe 4 ). The built-in electric field (BIEF) generated at the NiFePBA/Fe 2 NiSe 4 heterojunction showed improved catalytic activity for OER, where the interface electron transfer was markedly enhanced. By modulating the degree of selenization, the inner BIEF intensity can be finely tuned, by which the lowest charge transfer resistance (R ct ) value (2.38 Ω) was obtained for NiFePBA/Fe 2 NiSe 4 -40. The optimized NiFePBA/Fe 2 NiSe 4 -40 structure demonstrated better electrocatalytic activity in 1 M KOH, achieving high current densities of 10 mA cm -2 and 100 mA cm -2 at low overpotentials of 275 mV and 350 mV, respectively. Additionally, the catalyst exhibited excellent stability and a low Tafel slope of 62.60 mV dec -1 . Our work provides new guidance and strategy for the development of high-performance OER catalysts.