N-Doped Carbon Shells Encapsulated Ru-Ni Nanoalloys for Efficient Hydrogen Evolution Reaction

Graphical Electrocatalytic HERo in the making : Synthesis of Ru 7 Ni 3 nanoalloys encapsulated within N-doped carbon shells (Ru 7 Ni 3 @NC/C) is achieved for the alkaline HER. It exhibits a current density of 10 mA cm −2 at 16 mV with a Tafel slope of 29.9 mV dec −1 , and robust durability over 10 000 cycles in 1 m KOH. The high HER activity of Ru 7 Ni 3 @NC/C can be attributed to the strong synergistic interaction, N-doped carbon shells structure with high surface area and electrical conductivity. The alkaline hydrogen evolution reaction (HER) is of great significance for the large-scale green H 2 production. Currently, pressing challenges in the fabrication of cost-effective HER electrocatalysts are related to their sluggish water dissociation kinetics. Herein, a facile strategy to accelerate the desorption of HER intermediates and water dissociation is proposed. RuNi nanoalloy confined within N-doped carbon shells (Ru 7 Ni 3 @NC/C) with optimized Ru/Ni ratio and the dicyandiamide dosage was prepared. It displays an overpotential ( η 10 ) of 16 mV, Tafel slope of 29.9 mV dec −1 , and long-term stability over 10 000 cycles. The decent HER performance on Ru 7 Ni 3 @NC/C stems from the core-shell structure that is favoring the exposure of dispersed active sites, and the synergistic effect to promote water capture and dissociation. This work provides insight into the relationship between the HER performance and the electrochemical behavior of the intermediate adsorbed state, and paves an avenue toward rational design efficient electrocatalysts for HER.