NiRh nanosponges with highly efficient electrocatalytic performance for hydrogen evolution reaction

Abstract 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 Ni x Rh y nanosponges while using NaBH 4 as a reducing agent without any surfactant. The ratio of Ni and Rh has been changed to obtain various Ni x Rh y electrocatalysts (Ni, Ni 3 Rh 1 , Ni 1 Rh 1 , Ni 1 Rh 3 , and Rh), respectively. Among the prepared catalysts, Ni 1 Rh 3 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 H 2 SO 4 electrolyte. In addition, the Ni 1 Rh 3 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 Ni 1 Rh 3 cathode and the commercial RuO 2 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.