Promoted Overall Water Splitting Catalytic Activity and Durability of Ni <sub>3</sub> Fe Alloy by Designing N‐Doped Carbon Encapsulation
Dong In Jeong, Ui Young Lee, Hyunchul Kim, Hyeon‐Seok Bang, Hyung Wook Choi, Jiwon Kim, Hyuck Gu Choi, Hyung‐Suk Oh, Bong Kyun Kang, Dae Ho Yoon
Abstract
Abstract 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 Ni 3 Fe@NCS catalyst with the N‐doped carbon shell, and the Ni 3 Fe catalyst. The synthesized Ni 3 Fe@NCS catalyst has a distinct overpotential difference from the Ni 3 Fe catalyst ( η OER = 468.8 mV, η HER = 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 Ni 3 Fe@NCS catalyst showed a stability of (95.47 and 99.6)%, while the Ni 3 Fe 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 Ni 3 Fe 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 Ni 3 Fe 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.