Rational design of hollow oxygen deficiency-enriched NiFe2O4@N/rGO as bifunctional electrocatalysts for overall water splitting

Bimetallic metal organic framework (MOF) as a precursor to prepare catalysts with bifunctional catalytic activity of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) attracts more and more attention. Herein, hollow oxygen deficiency-enriched NiFe2O4 is synthesized by pyrolytic FeNi bimetallic MOF. The defects of rGO during carbonization can act as nucleation sites for FeNi particles. After nucleation and N doping, the FeNi particles were served as catalysts for the deposition of dissolved carbon in the defects of the N/rGO. These deposited carbon, like a bridge, connect N/rGO and hollow oxygen deficiency-enriched NiFe2O4 together, which giving full play to the advantages of N/rGO in fast electron transfer, thereby improving its catalytic activity. The resultant NiFe2O4 @N/rGO-800 exhibits a low overpotential of 252 mV at 20 mA cm(2) for OER and 157 mV at 10 mA cm(2) for HER in 1 M KOH, respectively. When used as bifunctional electrodes for overall water splitting, it also shows low cell voltage of 1.60 V and 1.67 V at 10 and 20 mA cm(2), respectively. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

Utilizing bimetallic metal organic frameworks as precursors, catalysts with bifunctional catalytic activity of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) can be prepared. The synthesized NiFe2O4 demonstrates promising catalytic performance in 1 M KOH, suggesting potential application in overall water splitting reactions.