Vacancy-PBA derived nanoparticle containing defect-rich crystal structure and P, S dual-doping as an outstanding oxygen evolution electrocatalyst

Abstract

Herein, a uniquely-designed electrocatalyst containing a defect-rich crystal structure and P, S dual dopant (designated v-NiFe-PS) is synthesized for the oxygen evolution reaction (OER). The [Fe(CN)6] vacancy-PBA (v-PBA) precursor is simply synthesized via mixing and post-oxidation. The defect-rich crystal structure is provided by the v-PBA precursor, and the P, S dual doping provides a tailored electronic distribution around the metal active sites, thereby reducing the energy barrier for the OER. This is confirmed by comparison of the v-NiFe-PS with single-doped v-NiFe-P and v-NiFe-S, and with NiFe-PS derived from non-vacancy PBA. As a result, the v-NiFe-PS exhibits the lowest overpotential (263 mV) and Tafel slope (41 mA dec–1) compared to the comparison groups and the benchmark (RuO2). Furthermore, the v-NiFe-PS exhibits a robust stability during 100 charge/discharge cycles, and a low voltage gap of 0.93 V at 1.0 mA cm–2.