Adsorption of water vapour en a series of nickel-chromia samples has been studied. Nickel-chromia, with 15% chromium is an active catalyst for H-D (hydrogen-deuterium) exchange in hydrogen-water system, where water is in vapour phase. Water vapour adsorption/deserption indicate that it is adsorbed on the catalyst both physically and chemically. The 15% chromium catalyst sample has been treated with phenylethyl triethoxy silane to make it hydrophobic and active in liquid water-hydrogen system of H-D exchange. Water vapour adsorption isotherm on the treated sample shows the hydrophobization of the catalyst.