Boosting pH‐Universal Hydrogen Evolution of Molybdenum Disulfide Particles by Interfacial Engineering†

Main observation and conclusion The design of high‐efficiency non‐noble and earth‐abundant electrocatalysts for hydrogen evolution reaction (HER) is highly paramount for water splitting and renewable energy systems. Molybdenum disulfide (MoS 2 ) with abundant edge sites can be utilized as a promising alternative, but its catalytic activity is greatly related to the pH values, especially in an alkaline environment due to the extremely high energy barriers for water adsorption and dissociation steps. Here we report an exceptionally efficient and stable electrocatalyst to improve the sluggish HER process of layered MoS 2 particles in different pH electrolytes, especially in base. The electrocatalyst is constructed by in situ growing selenium‐doped MoS 2 (Se‐MoS 2 ) nanoparticles on three‐dimensional cobalt nickel diselenide (Co 0.2 Ni 0.8 Se 2 ) nanostructured arrays. Due to the large number of active edge sites of Se‐MoS 2 particles exposed at the surface, robust electrical conductivity and large surface area of Co 0.2 Ni 0.8 Se 2 support, and strong interfacial interactions between Se‐MoS 2 and Co 0.2 Ni 0.8 Se 2 , this hybrid catalyst shows very outstanding catalytic HER properties featured by low overpotentials of 30 and 122 mV at 10 and 100 mA/cm 2 with good operational stability in base, respectively, which outperforms most of inexpensive catalysts consisting of layered MoS 2 , transition metal selenides and sulfides, and it performs as well as noble Pt catalysts. Meanwhile, this electrocatalyst is also very active in neutral and acidic electrolytes, requiring low overpotentials of 93 and 94 mV at 10 mA/cm 2 , respectively, demonstrating its superb pH universality as a HER electrocatalyst with excellent catalytic durability. This study provides a straightforward strategy to construct an efficient non‐noble electrocatalyst for driving the HER kinetics in different electrolytes.