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초록

Developing cost-effective and efficient bifunctional electrocatalysts for water splitting remains a significant challenge in sustainable energy research. Herein, we present the hydrothermal synthesis of nickel selenide (NiSe2) and copper-doped nickel selenide (NiCuSe2), followed by systematic evaluation of their electrocatalytic activity toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Introduction of copper into NiSe2 markedly reduces the overpotentials to 316 mV for HER and 248 mV for OER at 10 mA/cm2 and decreases the Tafel slopes, reflecting improved reaction kinetics. Morphological characterization shows that NiCuSe2 possesses a porous, nanogranular structure, which increases the electrochemically active surface area. Incorporation of copper into nickel selenide decreases overpotential values by modulating the electronic structure of NiSe2, thereby optimizing the free energy for hydrogen adsorption. In summary, the inclusion of copper within the NiSe2 lattice substantially modifies the electronic characteristics and enhances the exposure of electroactive sites, thereby improving catalytic efficiency. Moreover, the NiCuSe2 catalyst demonstrates excellent durability and low charge transfer resistance, underscoring its potential as a highly effective bifunctional electrocatalyst for water splitting in alkaline environments.

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