Jaewon Lee , Yongseon Choi , Jiyoung Kim , Eunoak Park , Kiyoung Lee
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引用次数: 0
Abstract
Electrodeposition is a cost-effective method to fabricate water splitting catalysts, but achieving uniform nanostructure and durable electrodeposits remains challenging. In this study, Ni-Fe oxyhydroxide catalyst were electrodeposited on Ni foam via two-step metal dissolution electrodeposition (MDE) process in an ethylene glycol-water electrolyte with varying thiourea concentration (0∼0.15 M). The effect of thiourea on nucleation behavior, deposit morphology, composition, and oxygen evolution reaction (OER) performance was investigated using electrochemcial measurements and structural characterization. Thiourea profoundly affected the electrodeposition process. It shifted the nucleation mode from instantaneous to progressive, resulting in more uniformly distributed nanostructures. As a leveling agent, thiourea inhibited excessive deposition in high field regions, and as complex agent, it selectively promoted Ni2+ deposition, while suppressing Fe2+ incorporation. The optimum thiourea concentration (0.05 M) produced a catalyst with an OER overpotential of 286 mV at 100 mA/cm2 and a charge transfer resistance of 1.03 Ω, dramatically improved from 360 mV at 100 mA/cm2 and 21.6 Ω without thiourea. The addition of thiourea also increased the electrochemical active surface area and decreased the Tafel slope, indicating improved kinetics. In addition, the 0.05 M thiourea modified catalyst showed excellent durability, with no degradation in performance after 100 h at 100 mA/cm2. Thiourea is critical additive that enables controlled nucleation, selective metal deposition dramatically improves the nanostructure, activity, and durability of Ni-Fe OER catalyst, offering promising strategy for high-efficient water electrolysis.
期刊介绍:
Materials Today Sustainability is a multi-disciplinary journal covering all aspects of sustainability through materials science.
With a rapidly increasing population with growing demands, materials science has emerged as a critical discipline toward protecting of the environment and ensuring the long term survival of future generations.