Nickel Nanocrystal Assemblies as Efficient Electrocatalysts for Hydrogen Evolution from pH-Neutral Aqueous Solution

Earth-abundant elements based efficient and stable electrocatalyst for hydrogen generation from pH-neutral aqueous solutions is highly desired, but still a momentous task. Herein, we report a nickel nanocrystal assembled nanoparticles (Ni-SP) synthesis through a simple solution phase ultrasonic-assisted chemical reduction method. The addition of tungsten (W) metal as a non-3d high valency element and non-metals (B and P) as low valency element could modulate the hydrogen adsorption energy for efficient catalysis of the hydrogen evolution reaction (HER). For HER in pH-neutral buffer solution, the Ni-SP needs 38 and 214 mV overpotential to drive 10 and 100 mA cm(-2) current densities, respectively. Moreover, the catalytic activity of Ni-SP remains unaffected after 10 h of hydrogen production at 100 mA cm(-2) current density, presenting superior stability and activity as compared to Pt/C.