Ni3S2/Ball-milled Silicon Flour as a Bi-Functional Electrocatalyst, Hydrogen and Oxygen Evolution Reaction, Ali A. Ensafi, Mehdi Jafari-Asl, Afshin Nabiyan, B. Rezaei, Energy, 2016, 116, 392-401.

Elaborate  design  of  highly efficient  and  durable  electrocatalysts  from earth-abundant elements  is  a
milestone in the field of electrochemistry. In this study, heazlewoodite (Ni3S2) was successfully grafted
on the silicon flour (Ni3S2 @ SiF) and ball-milled silicon flour (Ni3S2 @ BeSiF) through a simple hydrothermal
process. The products were then etched using the HF solution to prepare the modified porous silicon
(PSi) compounds of Ni3S2 @ PSi and Ni3S2 @ BePSiF. Electrochemical studies showed that Ni3S2 @
BeSiF and Ni3S2 @ BePSiF were not only durable but also exhibited electrocatalytic activity toward both alkaline and
acidic  hydrogen  evolution  reactions  (HER)  with  appropriate  Tafel  slopes  of  74  and  52  mV  dec
1,
respectively. Moreover, they recorded an electrocatalytic activity for the oxygen evolution reaction (OER)
with an overpotential of 164 mV dec
1 . Based on the electrocatalytic studies, the Ni3S2 @BePSiF electro-
catalyst was found to have the best electrocatalytic behavior toward HER and OER. The isolated island
architecture of the bi-functional (i.e., HER and OER) electrocatalyst could act as promising electrode
materials for water splitting using electrochemical methods.