Graphene-nanoplatelets-supported NiFe-MOF: high-efficiency and ultra-stable oxygen electrodes for sustained alkaline anion exchange membrane water electrolysis. Issue 10 (9th June 2020)

• Record Type: Journal Article
• Authors: Thangavel, Pandiarajan; Ha, Miran; Kumaraguru, Shanmugasundaram; Meena, Abhishek; Singh, Aditya Narayan; Harzandi, Ahmad M.; Kim, Kwang S.
• Is Part Of: Energy & environmental science. Volume 13:Issue 10(2020)
• Page Start: 3447
• Page End: 3458
• Publication Date: 2020-06-09
• Subjects: Energy conversion -- Periodicals; Fuel switching -- Periodicals; Environmental sciences -- Periodicals; Environmental chemistry -- Periodicals; 333.79
• DOI: 10.1039/d0ee00877j
• Languages: English
• ISSNs: 1754-5692

Abstract

Abstract : A simple and effective strategy for fabricating high-stability alkaline anion exchange membrane water electrolyzers for large-scale hydrogen production. Abstract : Practical hydrogen production using high-efficiency, low-cost, and stable oxygen electrodes is crucial for a sustainable clean energy future. Herein we report a graphene-nanoplatelets-supported (Ni, Fe) metal–organic framework (MOF) as a superior and ultra-durable (>1000 h) anode for alkaline water electrolysis. The MOF on carbon-fiber paper electrodes requires an overpotential η = 220 mV to achieve a current density j = 10 mA cm −2 ( η = 180 mV on nickel foam for j = 20 mA cm −2 ) with a Tafel slope of 51 mV per decade, high turnover frequency (1.22 s −1 ), high faradaic efficiency (99.1%), and long-term durability of >1000 h in continuous electrolysis. In an alkaline anion exchange membrane water electrolyzer (AAEMWE), it exhibits a record current density of 540 mA cm −2 at 1.85 V at 70 °C, outperforming the state-of-the-art Pt/C//IrO2 . A breakthrough strategy introduced in membrane electrode assembly fabrication by extending the electrical contact with an aqueous electrolyte offers an additional OH − transport pathway to regenerate the original conductivity of the AAEMWE in continuous electrolysis, without any significant change in the pH of the electrolyte. These findings open up durable, high-performance AAEMWE and direct solar-to-fuel conversion, especially to replace high-cost proton exchange membrane water electrolysis that already works with ultra-pure water.