One-pot synthesis of Fe3O4@graphite sheets as electrocatalyst for water electrolysis

In this study, Fe3O4@graphite sheets were successfully synthesized in one-pot via a simple hydrothermal method and subsequently employed as an effective electrocatalyst for hydrogen evolution reaction (HER). HER is the crucial electrochemical reactions for the next-generation energy devices. Hydrogen is a clean and renewable energy resource and is one of the most promising candidates for fuel. The shape of the Fe3O4 nanoparticles is nearly spherical with a size of about 10 nm and the Fe3O4 nanoparticles distributed evenly on the graphite sheets. The synthesized Fe3O4@graphite sheets have a specific surface area about 125 m(2) g(-1) with slit-shaped open micro/mesopores. Overall the physicochemical characterization techniques have confirmed the formation, structural stability, and elemental composition of synthesized Fe3O4@graphite sheets. The resulting Fe3O4@graphite sheets were demonstrated towards electrocatalytic HER in 0.1 M KOH solution. The synthesized Fe3O4@graphite sheets delivered the lowest Tafel slope (78 mV dec(-1)) and overpotential (-120 mV(RHE)) at a current density of 10 mA cm(-2). The electrochemical impedance spectroscopy results demonstrate that HER are highly favorable on the Fe3O4@graphite sheets due to the relatively low charge transfer resistance. The experimental results reveal that Fe3O4@graphite sheets possess remarkable electrocatalytic HER activities and are highly stable. The good electrocatalytic activity of Fe3O4@graphite sheet can be ascribed to the synergistic effect between Fe3O4 and graphite sheets, which can facilitate charge transfer kinetics to enhance electrocatalytic HER performance.