Ambient Temperature Synthesis of Iron-Doped Porous Nickel Pyrophosphate Nanoparticles with Long-Term Chemical Stability for High-Performance Oxygen Evolution Reaction Catalysis and Supercapacitors

Recently, transition-metal phosphides and phosphates have been recognized as candidates for electrochemical energy storage and conversion application. However, the preparation of such materials usually requires high energy consumption and toxic precursors which are considered to be drawbacks for real applications. In this study, we report ambient temperature synthesis of transition-metal phosphates for oxygen evolution reaction (OER) and supercapacitors. The prepared iron-doped porous nickel pyrophosphate (NFPy) nanoparticle is synthesized via simple stirring in ambient temperature using only the precursor for Ni, Fe, and pyrophosphate without any heat treatment. The usage of pyrophosphate promotes facile Ni oxidation and high chemical stability, which overall is beneficial for electrochemical applications and the environment. The OER performance of NFPy shows promising results which required an overpotential of 0.210 V to reach 10 mA.cm(-2). Also, with the help of carbon nanotubes, the supercapacitor using NFPy exhibits a good electrochemical performance with a capacity of 517 C.g(-1) at 1 A.g(-1). The prepared NFPy possesses excellent long-term chemical stability that maintained its chemical valence state and electrochemical performance for over 8 months despite the exposure of air.