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 Ni3 Fe@NCS catalyst with the N-doped carbon shell, and the Ni3 Fe catalyst. The synthesized Ni3 Fe@NCS catalyst has a distinct overpotential difference from the Ni3 Fe 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 Ni3 Fe@NCS catalyst showed a stability of (95.47 and 99.6)%, while the Ni3 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 Ni3 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 Ni3 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.
Keywords: N-doped carbon shell; hydrogen evolution reaction; overall water splitting; oxygen evolution reaction; transition metal alloy.
© 2024 Wiley-VCH GmbH.