Cobalt-Nanocrystal-Assembled Hollow Nanoparticles for Electrocatalytic Hydrogen Generation from Neutral-pH Water.

Highly active and stable electrocatalysts for hydrogen generation from neutral-pH water are highly desired, but very difficult to achieve. Herein we report a facile synthetic approach to cobalt nanocrystal assembled hollow nanoparticles (Co-HNP), which serve as an electrocatalyst for hydrogen generation from neutral-pH water. An electrode composed of Co-HNP on a carbon cloth (CC) produces cathodic current densities of 10 and 100 mA cm(-2) at overpotentials of -85 mV and -237 mV, respectively. The Co-HNP/CC electrode retains its high activity after 20 h hydrogen generation at a high current density of 150 mA cm(-2) , indicating the superior activity and stability of Co-HNP as electrocatalyst.