Bifunctional Electrocatalysts for Overall Water Splitting from an Iron/Nickel-Based Bimetallic Metal-Organic Framework/Dicyandiamide Composite

Xiaojia Zhao; Pradip Pachfule; Shuang Li; Jan Ron Justin Simke; Johannes Schmidt; Arne Thomas

doi:10.1002/anie.201803136

Bifunctional Electrocatalysts for Overall Water Splitting from an Iron/Nickel-Based Bimetallic Metal-Organic Framework/Dicyandiamide Composite

Angew Chem Int Ed Engl. 2018 Jul 16;57(29):8921-8926. doi: 10.1002/anie.201803136. Epub 2018 Jun 19.

Authors

Xiaojia Zhao¹, Pradip Pachfule¹, Shuang Li¹, Jan Ron Justin Simke², Johannes Schmidt¹, Arne Thomas¹

Affiliations

¹ Functional Materials, Department of Chemistry, Technische Universität Berlin, Hardenbergstrasse 40, 10623, Berlin, Germany.
² Zentraleinrichtung Elektronenmikroskopie (ZELMI), Technische Universität Berlin, Strasse des 17. Juni 135, 10623, Berlin, Germany.

PMID: 29714400
DOI: 10.1002/anie.201803136

Abstract

Pyrolysis of a bimetallic metal-organic framework (MIL-88-Fe/Ni)-dicyandiamide composite yield a Fe and Ni containing carbonaceous material, which is an efficient bifunctional electrocatalyst for overall water splitting. FeNi₃ and NiFe₂ O₄ are found as metallic and metal oxide compounds closely embedded in an N-doped carbon-carbon nanotube matrix. This hybrid catalyst (Fe-Ni@NC-CNTs) significantly promotes the charge transfer efficiency and restrains the corrosion of the metallic catalysts, which is shown in a high OER and HER activity with an overpotential of 274 and 202 mV, respectively at 10 mA cm^-2 in alkaline solution. When this bifunctional catalyst was further used for H₂ and O₂ production in an electrochemical water-splitting unit, it can operate in ambient conditions with a competitive gas production rate of 1.15 and 0.57 μL s^-1 for hydrogen and oxygen, respectively, showing its potential for practical applications.

Keywords: bifunctional electrocatalyst; carbon nanotubes; meso-/macroporous carbons; metal-organic frameworks (MOFs); overall water splitting.