In-situ synthesis of conductive Fe-MOFs on the carbon nanotubes/carbon cloth as high-performance catalyst for alkaline oxygen evolution

In the electrolysis of water, the efficiency is heavily constrained by the slow kinetic process of the oxygen evolution reaction (OER) at the anode. Herein, by a simple hydrothermal method for the in-situ growth of Fe3(HHTP)2 on the open three-dimensional nanostructured substrate, Co-anchored carbon nanotubes/carbon cloth (Co/CNT/CC), Fe3(HHTP)2@Co/CNT/CC was prepared and acted as an OER electrocatalyst. The combination of carbon nanotubes (CNTs) and carbon cloth not only enhanced the substrate conductivity, but also facilitated the uniform loading of Fe3(HHTP)2. The in-situ growth, on the other hand, allowed the Fe3(HHTP)2 to connect with the conductive substrate tightly, thus enhancing the stability of the interfacial contact, improving the electron transfer efficiency and providing enough catalytically active sites. In addition, the construction of self-supported electrodes could effectively avoid the use of binders and improve the stability of the composites during electrolysis. The Fe3(HHTP)2@Co/CNT/CC displayed excellent properties in alkaline electrolytes as an efficient OER catalyst, achieving a current density of 50 mA cm-2 at an overpotential of only 1.60 V and perfect stability in long-term tests. Herein, the present work provides a rational tactics for developing self-supporting electrodes with plentiful active sites and high stability to enhance the electrochemical efficiency of water splitting.