Promoted Overall Water Splitting Catalytic Activity and Durability of Ni3Fe Alloy by Designing N‐Doped Carbon Encapsulation

Combining an electrochemically stable material onto the surface of a catalyst can improve the durability of a transition metal catalyst, and enable the catalyst to operate stably at high current density. Herein, the contribution of the N‐doped carbon shell (NCS) to the electrochemical properties is evaluated by comparing the characteristics of the Ni3Fe@NCS catalyst with the N‐doped carbon shell, and the Ni3Fe catalyst. The synthesized Ni3Fe@NCS catalyst has a distinct overpotential difference from the Ni3Fe catalyst (ηOER = 468.8 mV, ηHER = 462.2 mV) at (200 and −200) mA cm−2 in 1 m KOH. In stability test at (10 and −10) mA cm−2, the Ni3Fe@NCS catalyst showed a stability of (95.47 and 99.6)%, while the Ni3Fe catalyst showed a stability of (72.4 and 95.9)%, respectively. In addition, the in situ X‐ray Absorption Near Edge Spectroscopy (XANES) results show that redox reaction appeared in the Ni3Fe catalyst by applying voltages of (1.7 and −0.48) V. The decomposition of nickel and iron due to the redox reaction is detected as a high ppm concentration in the Ni3Fe catalyst through Inductively Coupled Plasma Optical Emission Spectroscopy (ICP−OES) analysis. This work presents the strategy and design of a next‐generation electrochemical catalyst to improve the electrocatalytic properties and stability. Forming N‐doped carbon shells on the catalyst surface is a promising method to improve the stability of electrochemical catalysts. Additionally, the carbon shell suppresses the phase change of the transition metal catalyst, significantly reducing the amount of catalyst dissolved in the electrolyte. This study demonstrates the role of the carbon shell as a strategy to maintain durability and catalytic properties.