Hollow FeP/Fe<sub>3</sub>O<sub>4</sub> Hybrid Nanoparticles on Carbon Nanotubes as Efficient Electrocatalysts for the Oxygen Evolution Reaction
Jie Yu, Tao Zhang, Yiqiang Sun, Xuejiao Li, Xinyang Li, Bo Wu, Dandan Men, Yue Li
Abstract
We develop a method to prepare hollow FeP/Fe3O4 hybrid nanoparticles supported on carbon nanotubes (CNTs), which could be used as highly active and efficient electrocatalysts. The Fe@Fe3O4/CNT hybrids were first synthesized by annealing the CNTs adsorbed with Fe(NO3)3, followed by controlled phosphorization treatment. They exhibit an outstanding catalytic activity for oxygen evolution reaction (OER) with a low overpotential of 229 mV at a current density of 10 mA cm–2, a high turnover frequency value of 0.35 s–1 at an overpotential of 300 mV, and an ultralow Tafel slope of 27.6 mV dec–1, which is much better than that of FeP/Fe3O4, FeP/CNTs, Fe3O4/CNTs, and the commercial RuO2 electrocatalyst. More importantly, the Tafel slope is much lower than most non-noble metal-based OER electrocatalysts reported in the previous literature studies as far as we know. The excellent OER performance benefits from the electron transfer from Fe3O4 to FeP confirmed by X-ray photoelectron spectroscopy, together with good conductivity of CNTs. This hybrid structure supported on conductive CNTs may offer an efficient method to design earth-abundant and low-cost electrocatalysts for OER in practical applications.