Construction of high activity electrocatalyst for alkaline hydrogen evolution by doping magnetic Fe3O4 with RuO2

Abstract

Abstract The rational build of hydrogen evolution reaction (HER) electrocatalyst with low-cost, highly efficient, and excellent stability is the key to realizing the electrochemical decomposition of water. Herein, the optimal ratio between RuO2 and Fe3O4 for high-activity electrocatalysts (RuO2/Fe3O4 hybrid nanoparticles) was obtained by the microemulsion method. The morphology and structure characterization show uniform distribution (average particle size of ∼35.0 ± 5.1 nm) and high crystallinity of the RuO2/Fe3O4 hybrid nanoparticles. Compared to RuO2/Fe3O4 (2:1) and RuO2/Fe3O4 (1:2) samples, electrochemical tests show that RuO2/Fe3O4 (1:1) exhibit favorable HER catalytic activity (overpotential: 181 mV at 10 mA cm−2; Tafel slope: 130 mV dec−1) and stability (no obvious activity attenuation during the 20 h) in an alkaline medium. The mechanism analysis implies that the doping of Fe3O4 accelerated the electron transfer rate and thus increased HER activity via the results of electrochemical impedance spectroscopy (EIS) tests. Blending the appropriate amount of Fe3O4 into RuO2 can not only reduce the cost of electrocatalyst but also improve the activity of electrocatalytic HER, which is expected to give guidance for the development of low-cost, highly stable nanostructured electrocatalysts for electrochemical HER in alkaline electrolytes.