Graphene-nanoplatelets-supported NiFe-MOF: high-efficiency and ultra-stable oxygen electrodes for sustained alkaline anion exchange membrane water electrolysis

By P. Thangavel, Miran Ha, S. Kumaraguru, Abhishek Meena, A. Singh, A. M. Harzandi, Kwang Soo Kim. 2020

143 citations recorded by the source corpus.

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.

Subfields: Electrical and Electronic Engineering, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/30223e2114ba663802be11ea82f4d4cbf785f265