Enhanced Hydrogen Evolution Catalysis at the Liquid/Liquid Interface by Ni x S y and Ni x S y /Carbon Nanotube Catalysts

Ni x S y (NiS and Ni 17 S 18 ) nanoparticles and their nanocomposite with carbon nanotubes (Ni x S y /CNT) were synthesized by a modified hydrothermal method and characterized by X‐ray diffraction, Raman spectroscopy, scanning electron microscopy, and energy‐dispersive X‐ray microanalysis. The synthesized materials were used as hydrogen evolution catalysts at the water/1,2‐dichloroethane interface by using decamethylferrocene as a lipophilic electron donor. The hydrogen evolution reaction in biphasic systems was investigated by two‐phase reactions and by cyclic voltammetry with a four‐electrode system. A kinetic study of the hydrogen production was also performed. The rates of the reactions catalyzed by the Ni x S y nanoparticles and the Ni x S y /CNT nanocomposite were found to be about 690‐fold and 2000‐fold higher, respectively, than the rate for the reaction performed in the absence of a catalyst.