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Transition metal selenides have garnered considerable attention in the field of electrocatalytic oxygen evolution reaction (OER). However, their OER performances still lag behind those of Ir-based materials due to limited exposed active sites, inefficient electron transfer and inadequate stability. In this study, we have successfully synthesized nitrogen-doped NiSe2 nanosheets, which exhibit high efficiency and long-term stability for the OER, requiring only 320 mV to reach a current density of 10 mA cm−2. The nitrogen doping plays a crucial role in effectively regulating the work function and semiconductor characteristics of NiSe2, which facilitates the electron transport and optimizes the catalytic sites. Furthermore, the NiSe2 nanosheets present a larger surface area with more exposed active sites, thus resulting in exceptional OER catalytic activity. The nitrogen-doped NiSe2 nanosheets also display superior stability, maintaining a sustained current density throughout an 8-h OER operation. [ABSTRACT FROM AUTHOR]

The lack of an efficient and stable electrocatalyst for oxygen evolution reaction (OER) greatly hinders the development of various electrochemical energy conversion and storage techniques. In this study, we report a facile synthesis of FeCoNiCuIr high-entropy alloy nanoparticles (HEA NPs) by a one-step heat-up method. The involvement of glucose made the NPs grow uniformly and increased the valence of Ir. The resulting FeCoNiCuIr NPs exhibit excellent OER performance in alkaline solution, with a low overpotential of 360 mV to achieve a current density of 10 mA cm−2 at a Tafel slope of as low as 70.1 mV dec−1. In addition, high stability has also been observed, which remained at 94.2% of the current density after 10 h constant electrolysis, with a constant current of 10 mA cm−2. The high electrocatalytic activity and stability are ascribed to the cocktail effect and synergistic effect between the constituent elements. Our work holds the potential to be extended to the design and synthesis of high-performance electrocatalysts. [ABSTRACT FROM AUTHOR]