Pulsed laser-assisted synthesis of defect-rich NiFe-based oxides for efficient oxygen evolution reaction

Abstract

To develop highly efficient and low-cost electrocatalysts based on earth-abundant elements for oxygen evolution reaction (OER) is a great challenge for electrocatalytic water splitting. Herein, a unique type of NiFe-based oxide catalyst with abundant defects is successfully synthesized via pulsed laser ablation in a specific atmosphere containing reductive NH3. The catalyst is self-supported and assembled from ultrafine nanoparticles with size of less than 5 nm. X-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy analyses suggest that the reductive NH3 results in a large number of oxygen and nickel vacancies and lower crystallinity. Consequently, the catalyst exhibits a high-performance OER activity with a low overpotential of 223 mV at 10 mA cm−2 and a small Tafel slope of 35.0 mV dec−1, surpassing most NiFe-based OER electrocatalysts.