Interface-Engineered CoFe-Based Phosphide Electrocatalysts Derived from MOFs for Enhanced Hydrogen Evolution Reaction Performance

Abstract

The hydrogen evolution reaction (HER) is an efficient and low-cost key half-reaction in water electrolysis that can be a potential way of the long-term sustainable system of hydrogen production in future. In the present work, a well-designed bimetallic CoFe phosphide catalyst prepared by a controlled pyrolysis-phosphorization method was applied to well-designed metal organic structures (MOF) precursor. For improving electrochemical activity of catalyst, carbonization of Fe-doped ZIF-67 by dicyandiamide followed by modification with low temperature phosphidation by NaH2PO2 will be performed. The electrochemical activity of CoFe/HNC-P material is recorded in 1.0 M KOH solution with electrocatalytic activity for HER with an overpotential of 90 mV at 10 mAcm-2 and OER with an overpotential of 313 mV at 50 mAcm-2 with Tafel slopes of 84.7 and 63.0 mVdec-1, respectively. The improved performance is attributed to Fe-induced nucleation of CNTs along with synergetic effect of bimetallic heterointerfaces and hierarchical porosity. XRD shows that codeposited material consists of a mixed phase of phosphide and metal phases well dispersed inside the material, while HRTEM and XPS confirm the existence of well distributed metallic phases inside the material. The real application of our material for water splitting is guaranteed by the terminal performance obtained from the auxiliary information of full-cell water splitting and FEs. The interface-engineering strategy provides a general method to design MOFMOF-based electrocatalysts and apply them as bifunctional catalysts for the water splitting reaction.