Catalytic activity of Ni3S2 and the effects of reactor wall in the hydrogen production from water were investigated under hydrothermal conditions using hydrogen sulphide (H2S) as a reductant. It was found that Ni3S2 catalysed the hydrogen production from water and may act as a semi-conductor catalyst. In the case of addition of Ni3S2, the time required to achieve the maximum hydrogen yield significantly decreased and the maximum hydrogen yield increased. These results suggest that the Ni3S2 formed as a corrosion product of the reactor wall when using the Hastelloy C-276 lined reactor should play a catalytic role in the hydrogen production. These results could facilitate studies for the synthesis of highly active catalysts for the production of hydrogen under mild conditions. (C) 2012 Elsevier Ltd. All rights reserved.