Ni17W3–W Interconnected Hybrid Prepared by Atmosphere- and Thermal-Induced Phase Separation for Efficient Electrocatalysis of Alkaline Hydrogen Evolution

The development of efficient and stable noble-metal-free electrocatalysts for hydrogen evolution reaction (HER) in alkaline media is still a challenge. Herein, a hybrid material formed by the interconnection of Ni 17 W 3 intermetallic compound with metallic W is demonstrated for HER. The Ni 17 W 3 –W hybrid is prepared by the atmosphere- and thermal-induced phase-separation strategy from a single-phase precursor (NiWO 4 ), which gives Ni 17 W 3 –W hybrid abundant and tight interfaces. The theoretical calculation manifests that Ni 17 W 3 shows more optimized energetics for adsorbed H atom, while W has lower energy barrier for water dissociation, and the synergistic effect between them is believed to facilitate the HER kinetics. Moreover, Ni 17 W 3 presents a proper adsorption strength for both adsorbed OH and H, and thus Ni 17 W 3 may also act as a high HER catalyst by itself. As a result, the Ni 17 W 3 –W hybrid demonstrates high activity and durability for HER in liquid alkaline electrolyte; the electrolyzer assembled by Ni 17 W 3 –W hybrid and Ni–Fe-layered double hydroxide (LDH) as, respectively, the cathode and anode electrocatalysts presents superior performance to Pt/C–IrO 2 benchmark. In addition, the Ni 17 W 3 –W hybrid also works well in the water electrolyzer based on solid hydroxide exchange membrane. The present work provides a promising pathway to the design of high-performance electrocatalysts.