Hydrothermal Fabricated Ni₃S₄–Yb₂O₃ Heterojunction Electrocatalysts with Charge Redistribution for Efficient Alkaline Oxygen Evolution Reactions

Designing efficient and stable oxygen evolution reaction (OER) catalysts is of great significance for hydrogen production technology through the electrolysis of water. Nickel sulfide (Ni x S y ) has garnered considerable attention as an OER electrocatalyst owing to its high electrical conductivity and distinctive structure. Herein, Ni 3 S 4 –Yb 2 O 3 on nickel foam electrocatalysts was fabricated through a hydrothermal synthesis approach to optimize the performance of Ni 3 S 4 . The incorporation of Yb 2 O 3 induced charge redistribution within Ni 3 S 4, expanded the active surface area, and enhanced the availability of active sites. Consequently, the Ni 3 S 4 –Yb 2 O 3 /NF catalyst demonstrates exceptional electrocatalytic performance in 1 M KOH, attaining a current density of 10 mA cm –2 at a minimal overpotential of 148 mV, along with an ultralow Tafel slope of 47.3 mV dec –1 . In addition, we have confirmed that another reason for the improved performance is that Yb 2 O 3, as an electron donor, can effectively regulate the defects of the Ni atoms. This work offers a feasible strategy for developing highly effective OER electrocatalysts in alkaline media.