NiRh nanosponges with highly efficient electrocatalytic performance for hydrogen evolution reaction

The development of Ni-based nanoalloys has been extensively explored due to their low cost, high activity, and durability in the hydrogen evolution reaction (HER). Structural design of Ni-based nanoalloys is a promising approach to attain excellent electrocatalytic activity as well as stability of these catalysts. This study reports a facile method to prepare NixRhy nanosponges while using NaBH4 as a reducing agent without any surfactant. The ratio of Ni and Rh has been changed to obtain various NixRhy electrocatalysts (Ni, Ni3Rh1, Ni1Rh1, Ni1Rh3, and Rh), respectively. Among the prepared catalysts, Ni1Rh3 electrocatalyst exhibits a high electrocatalytic activity with an overpotential of 48 mV at a current density of −10 mA cm−2 and a superior stability even after 2000 cycles of CV in 0.5 M H2SO4 electrolyte. In addition, the Ni1Rh3 electrocatalyst shows good electrocatalytic activity in 1.0 M KOH electrolyte compared to commercial Pt/C (20 wt% of Pt) (c-Pt/C). Moreover, the overall water splitting system of the Ni1Rh3 cathode and the commercial RuO2 anode is evaluated, not only exhibiting excellent performance with a potential of 1.52 V at a current density of 10 mA cm−2, but also proving very stable operation for over 100,000 s in 1.0 M KOH electrolyte. [Display omitted] •NiRh alloy nanosponges are prepared using a facile method without any surfactant.•Rh-rich NiRh alloy nanosponges retain high crystallinity.•Electronic coupling between Ni and Rh atoms can enhance the HER activity.•NiRh nanosponges exhibit excellent HER performance.