Facile Spray‐Pyrolysis Synthesis of Yolk–Shell Earth‐Abundant Elemental Nickel–Iron‐Based Nanohybrid Electrocatalysts for Full Water Splitting

The development of high‐activity electrocatalysts for water splitting that comprise only inexpensive, earth‐abundant elements is critical but remains a daunting challenge. In this work, yolk–shell Ni 3 Fe/Ni 3 FeN was prepared by a spray‐pyrolysis technique, which could be scaleable. The yolk–shell Ni 3 Fe/Ni 3 FeN presents excellent catalytic activity for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) with overpotentials of 268 and 166 mV at 10 mA cm −2 , respectively, and bears a prominent electrochemical durability. Overall water splitting with an electrolyzer containing the yolk–shell Ni 3 Fe/Ni 3 FeN as the cathode and anode only requires a cell voltage of 1.62 V to reach a current density of 10 mA cm −2 . The present research not only introduces a new route for the synthesis of advanced functional electrocatalysts for overall water splitting but also sheds light on their potential commercial applications.