Worm-like S-doped RhNi alloys as highly efficient electrocatalysts for hydrogen evolution reaction

Abstract

Precious metals are considered as the most efficient electrocatalysts for boosting the dynamic process of cathode in water electrolysis devices. Due to the large surface areas and the low coordination numbers of surface atoms, their one-dimensional ultrafine nanowires and two-dimensional ultrathin nanosheets are continually being investigated, while stacking problems inevitably affect their activities and stabilities. We describe herein a three-dimensional metal network electrocatalyst consisting of a worm-like S-doped RhNi alloy (S-RhNi), which improves the performance for hydrogen evolution reaction (HER). Experimental results reveal that S-RhNi exhibits Pt-like HER activity with an onset potential close to 0 mV and a Tafel slope of 24.61 mV dec−1 in 0.5 M H2SO4 aqueous solution, having also good stability. The polarization curve shifts only 3.9 mV at a current density of −60 mA cm−2 after 1,000 cycles and the potential displays a slight change after holding the current density at −20 mA cm−2 for 10 h. This improved performance is supposed to be originated from the combination between the worm-like RhNi alloy, doped S atoms, and the three-dimensional structure. Overall, the results obtained and the facile synthesis methods offer a promising electrocatalyst for scaling-up hydrogen evolution. © 2019 Elsevier B.V.