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 Ni17W3 intermetallic compound with metallic W is demonstrated for HER. The Ni17W3-W hybrid is prepared by the atmosphere- and thermal-induced phase-separation strategy from a single-phase precursor (NiWO4), which gives Ni17W3-W hybrid abundant and tight interfaces. The theoretical calculation manifests that Ni17W3 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, Ni17W3 presents a proper adsorption strength for both adsorbed OH and H, and thus Ni17W3 may also act as a high HER catalyst by itself. As a result, the Ni17W3-W hybrid demonstrates high activity and durability for HER in liquid alkaline electrolyte; the electrolyzer assembled by Ni17W3-W hybrid and Ni-Fe-layered double hydroxide (LDH) as, respectively, the cathode and anode electrocatalysts presents superior performance to Pt/C-IrO2 benchmark. In addition, the Ni17W3-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.