Electrochemical integration of amorphous NiFe (oxy)hydroxides on surface-activated carbon fibers for high-efficiency oxygen evolution in alkaline anion exchange membrane water electrolysis

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2021-06, Vol.9 (24), p.1443-1451
• Main Authors: Thangavel, Pandiarajan, Kim, Guntae, Kim, Kwang S
• Format: Article
• Language: English
• Subjects: Activated carbon; Anion exchange; Anion exchanging; Carbon fibers; Catalysts; Commercialization; Durability; Efficiency; Electrical conductivity; Electrical resistivity; Electrochemistry; Electrodes; Electrolysis; Hydroxides; Integration; Iron compounds; Kinetics; Mass transport; Membranes; Nickel compounds; Oxygen; Oxygen evolution reactions; Renewable fuels; Solar energy; Solar energy conversion; Sustainability; Synergistic effect; Transport properties; Water splitting
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d1ta02883a

Developing practical water-splitting devices that convert earth-abundant solar energy and water into renewable fuel holds promise for a sustainable energy future; however, its successful commercialization for practical applications is limited by the sluggish kinetics of the oxygen evolution reaction (OER). Herein, we developed a high-efficiency and low-cost three-dimensional (3D) OER electrode via electrochemical integration of amorphous NiFeOOH on surface activated carbon fiber paper (CFP). The as-synthesized 3D-a-NiFeOOH/N-CFP electrode exhibits an ultra-low overpotential η (O 2 ) of 170 mV to afford 10 mA cm −2 current density, together with a Tafel slope of 39 mV per decade, and excellent stability under OER conditions. Apart from the synergistic effect, the excellent OER activity of a-NiFeOOH/N-CFP is attributed to the unique 3D structure with enriched active sites and the improved electrical conductivity that facilitates the fast OER kinetics and mass transport properties. As a result, the catalyst achieves a high turnover frequency (TOF) of 0.99 s −1 and mass activity ( j m ) of 2527 A g −1 at η (O 2 ) 270 mV, which outperforms so far reported state-of-the-art OER catalysts and commercial IrO 2 . Besides, an alkaline anion exchange membrane water electrolyzer fabricated with the a-NiFeOOH/N-CFP anode delivers 1 A current at 1.88 V with a long-term durability of 240 h. These findings highlight the design of high-efficiency OER catalysts and significant advancements towards the utilization of NiFeOOH catalysts for commercial applications. Designing a high-efficiency and low-cost three-dimensional (3D) OER electrode via electrochemical integration of amorphous NiFeOOH on surface activated carbon fibers.