In-system synthesize Fe nanodots-doped Ni hydroxide nanoflakes on Ni foam for efficient oxygen evolution catalysis

Abstract

Synthesizing catalytic electrode directly in H2O splitting system shows promising perspective for obtaining high-compatible and low-cost electrode via a more green and simple way. In this work, inspired by biological evolution phenomenon, we develop a simple electrochemical “stimulation-evolution” mechanism and successfully fabricate Fe nanodots-doped Ni hydroxide nanoflakes film electrode under a real-time oxygen evolution reaction (OER) situation in alkaline KOH electrolyte. Physical characterizations show that the film product is composed by Ni(OH)2 ultrathin nanoflakes with Fe hydroxide nanodots evenly doped, which shows combined properties of hierarchical nanostructure, 3D porous framework and enhanced affinity/conductivity. Being adopted as additive-free electrode, the product exhibits greatly improved OER catalytic activity with low onset overpotential, low Tafel slope of 43.5 mV dec−1, promising repairability/recyclability and high energy conversion efficiency. The in-situ electrochemical research shows a high compatibility of electrode and indicates that the fast OER kinetics is mainly ascribed to the severely reduced reaction resistance, which is further supported by density functional calculations. In-situ Raman study reveals a dynamic changes of material/H2O status on electrode interface during OER process. The as-proposed strategy, from view of methodology, may have great value on synthesizing other efficient catalytic film products.