Branch-leaf-shaped CuNi@NiFeCu nanodendrites as highly efficient electrocatalysts for overall water splitting

Engineering structural and electronic properties of electrocatalysts is a direct method to boost water splitting. Herein, distinctive branch-leaf-shaped CuNi@NiFeCu nanodendrites are successfully synthesized by a novel bionic design strategy. Importantly, this unique catalyst can display superior performance for overall water splitting, which only requires 42 mV at 10 mA cm-2 for hydrogen evolution reaction (HER) and 285 mV at 50 mA cm-2 for oxygen evolution reaction (OER). Further mechanism studies disclosed that Cu atoms in nanosheet edges not only act as key active sites for HER, but also draw electron in eg orbital of Fe active sites, which weakens the adsorption strength of oxygen-intermediate and accordingly enhances OER activity. Moreover, the optimized structure can prevent the agglomeration of nanosheets, provide numerous crystalline-amorphous interfaces and oxygen vacancies, which is beneficial to the enhancement of reaction kinetics. This work paved an original strategy to improve the activity of 2D materials.