Fe/Ni bimetal organic framework as efficient oxygen evolution catalyst with low overpotential

Electrochemical water-splitting is an ideal strategy to produce the promising substitutable energy source, hydrogen (H-2). However, the sluggish kinetics of electrochemical oxygen evolution reaction (OER) and the prohibitive cost, low reserves and easy oxidation of noble metal-based electrocatalysts force researchers to explore efficient and low-cost electrocatalysts. Bimetal nanostructred materials are proved to have enhanced OER catalytic performances. In this study, a series of bimetallic metal-organic frameworks (Fe/Ni-MOFs) are prepared by a solvothermal method. The prepared MOFs present abundant unsaturated metal active sites for OER. The optimized Fe/Ni bimetal-MOF has low overpotentials of 236 mV at 10 mA cm(-2) and 284 mV at 100 mA cm(-2) for OER In addition, in comparison with most of the previously reported OER electrocatalysts, the present MOF shows a lower Tafel slope of 49 mV dec(-1). Besides, the MOF catalyst exhibits high electrochemical stability and the OER activity shows a negligible change after stability test for 15 h and 10,000 voltammetric cycles. Meanwhile, the Fe-doped Ni-MOFs show faster catalytic kinetics and higher conductivity than the monometallic Ni-MOF. This work paves a way to exploit bi- or multi-metallic MOFs with high conductivities and electrocatalytic performances for electrochemical energy conversion. (C) 2019 Elsevier Inc. All rights reserved.