Ni 17 W 3 –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.