MoO3 was deposited over ZrO2 (SBET = 108 m(2) g(-1)) and ZrO(OH)(2) (SBET = 311 m(2) g(-1)) from its aqueous slurry to form saturation adsorption monolayers with densities of 3.2 and 3.5 Mo nm(-2), respectively. Samples were characterised by nitrogen physisorption, X-ray diffraction, and thiophene and benzothiophene hydrodesulphurisation (HDS). The deposited MoO3 stabilised the high surface area of the amorphous ZrO(OH)(2) after calcination but HDS activity was low. The activity Of MoO3 deposited over monoclinic ZrO2 was twice as high as that supported on Al2O3 in the reference commercial catalyst BASF M8-30. Furthermore, COO and NiO were successfully deposited over saturated MoO3/ZrO2 catalyst from aqueous slurries of their low-solubility carbonates and exhibited promotional effects of about 3 and 5, respectively. This deposition resulted in slightly higher HDS activities than obtained with conventional deposition from aqueous solutions of the respective nitrates. Although highest HDS activities over ZrO2-supported catalyst were achieved after selective deposition of Co and Ni acetylacetonates onto sulphided Mo samples, activity remained only as high as that of the commercial catalysts CoMo KF 756 and NiMo KF 846 supported on alumina. (c) 2007 Elsevier B.V All rights reserved.