Elaborate design of highly efficient and durable electrocatalysts from earthabundant elements is a milestone in the field of electrochemistry. In this study, heazlewoodite (Ni3S2) was successfully grafted on the silicon flour ((Ni3S2SiF)-Si-(a)) and ballmilled silicon flour ((Ni3S2SiF)-Si-(a)) through a simple hydrothermal process. The products were then etched using the HF solution to prepare the modified porous silicon (PSi) compounds of (Ni3S2PSi)-P-(a) and (Ni3S2B)-B-(a)-PSiF. Electrochemical studies showed that Ni3S2(a)-SiF and (Ni3S2B)-B-(a)-PSiF 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 (Ni3S2B)-B-(a)-PSiF electrocatalyst 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. (C) 2016 Elsevier Ltd. All rights reserved.