Core‐Shell Quantum Wires‐Supported Single‐Atom Fe Electrocatalysts for Efficient Overall Water Splitting

It is of great significance for the development of hydrogen energy technology by exploring the new-type and high-efficiency electrocatalysts (such as single atom catalysts (SACs)) for water splitting. In this paper, by combining interface engineering and doping engineering, a unique single atom iron (Fe)-doped carbon-coated nickel sulfide (Ni₃S₂) quantum wires (Ni₃S₂@Fe-SACs) is prepared as a high-performance bi-functional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Theoretical calculation and experimental results show that the addition of atomic Fe species can effectively adjust the electronic structure of sulfide, the interfacial electron transfer modulates the d-band center position, optimizing the transient state of the catalytic process and adsorption energy of hydrogen/oxygen intermediates, and greatly accelerates the kinetics of HER and OER. The results show that the Ni₃S₂@Fe-SACs core-shell quantum wires array exhibit overpotentials of 46 and 219 mV for HER and OER at 10 mA cm^-2 in 1 m KOH, respectively. In addition, the two-electrode electrolyzer assembled by the Ni₃S₂@Fe-SACs requires a voltage as low as 1.465 V to achieve alkaline overall water splitting of 10 mA cm^-2. This work holds great promise for the development of highly active and highly stable electrocatalysts for future hydrogen energy conversion applications.