FeOOH nanospheres decorated bimetallic NiFe-MOF as efficient dual-functional catalyst towards superior electrocatalytic performance

摘要

Exploring dual-functional metal-based hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalyst with high activity and stability is an indispensable strategy to effectively utilize hydrogen energy and alleviate energy crisis. Herein, a series of dual-functional NiFe-MOF@FeOOH-based composites with different electrodeposition intervals were synthesized via a solvothermal method and subsequent electrodeposition process. It was noted that when the electrodeposition time was set as 300 s, the corresponding composites exhibited the most effective OER catalytic activity with a low overpotential of 303 mV at 40 mA cm(-2). The optimal composites also displayed fast reaction kinetics with a small tafel plot of 36 mV dec(-1) and superior durability for 20 h. Meanwhile, the composite only required 137 mV for HER to reach a catalytic current density of 10 mA cm(-2) under the same condition. Clearly, the obtained composites depicted excellent dual-functional electrocatalytic performance which can be ascribed to its unique 3D hierarchical structure, larger electrochemical surface area, strong synergistic effect as well as improved electrical conductivity. Besides, the adopted FeOOH was favorable for the transformation from Ni2+ to Ni3+,which acted as the active centers of catalytic reaction to advance the OER process. All in all, this study provided a novel insight to design bimetallic MOF based electrode materials with both excellent HER and OER properties.