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

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 RuO 2 and Fe 3 O 4 for high-activity electrocatalysts (RuO 2 /Fe 3 O 4 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 RuO 2 /Fe 3 O 4 hybrid nanoparticles. Compared to RuO 2 /Fe 3 O 4 (2:1) and RuO 2 /Fe 3 O 4 (1:2) samples, electrochemical tests show that RuO 2 /Fe 3 O 4 (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 Fe 3 O 4 accelerated the electron transfer rate and thus increased HER activity via the results of electrochemical impedance spectroscopy (EIS) tests. Blending the appropriate amount of Fe 3 O 4 into RuO 2 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.