Bonding interface boosts the intrinsic activity and durability of NiSe@Fe2O3 heterogeneous electrocatalyst for water oxidation

The intrinsic activity and durability of oxygen evolution reaction (OER) electrocatalysts are mainly dominated by the surface and interface properties of active materials. Herein, a core-shell heterogeneous structure (NF/NiSe@Fe2O3) is fabricated via two-step hydrothermal method, which exhibits a low overpotential of 220 mV (or 282 mV) at 10 mA/cm(2) (or 200 mA/cm(2)), a small Tafel slope of 36.9 mV/dec, and long-term stability (-230 h) in 1 mol/L KOH for OER. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy reveal the (oxy)hydroxide-rich surface and strong coupling interface between NiSe and Fe2O3 via the Fe-Se bond. Density functional theory calculation suggests that the d-band center and electronic state of NiSe@Fe2O3 heterojunction are well optimized due to the formation of Fe-Se bond, which is favorable for the enhanced OER activity because of the easy adsorption of oxygen-containing intermediates and desorption of O-2 in the OER process. In addition, the unique core-shell structure and robust bonding interface are responsible for the good stability for OER. This work provides fundamental insights on the bonding effect that determine the performance of OER electrocatalyst. (C) 2020 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

Automated summary

A core-shell heterogeneous structure of oxygen evolution reaction (OER) electrocatalyst was fabricated in this study, showing low overpotential, small Tafel slope, and good long-term stability. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy revealed the Fe-Se bond at the interface, while density functional theory calculation indicated the favorable effect of this bonding on OER activity.