This work deals with the elaboration of heterogeneous catalysts in ionic liquids (ILs). These salts, liquid at room temperature, were chosen because they permit to adjust the solvent properties depending on their chemical composition (imidazolium salts or Deep Eutectic Solvent based on choline chloride and urea). These solvents allowed the synthesis and deposition of Au and Au-Pd nanoparticles (NPs) on TiO2. The IL nature controls the NPs stability in solution, the strength of the metal/support interaction and the nanostructuration of bimetallic particles. The catalysts performances, evaluated by selective hydrogenation, showed an increase in activity of the Au monometallic catalysts after addition of Pd, a promotion of the catalysts activity due to the presence of P residues from the ILs and an inhibition of the activity caused by S species. TiO2 supports were also prepared in DES. The use of this IL, in addition to a specific Ti precursor, led to a textural and structural control of the obtained polymorphs (anatase, rutile or anatase-rutile mixture). The influence of the support type was studied in CO oxidation after Au deposition by urea deposition-precipitation. The most active Au/TiO2 catalysts were obtained with anatase-rutile mixtures, the vicinity between anatase and rutile phases leading to an optimum activity and stability.This work deals with the elaboration of heterogeneous catalysts in ionic liquids (ILs). These salts, liquid at room temperature, were chosen because they permit to adjust the solvent properties depending on their chemical composition (imidazolium salts or Deep Eutectic Solvent based on choline chloride and urea). These solvents allowed the synthesis and deposition of Au and Au-Pd nanoparticles (NPs) on TiO2. The IL nature controls the NPs stability in solution, the strength of the metal/support interaction and the nanostructuration of bimetallic particles. The catalysts performances, evaluated by selective hydrogenation, showed an increase in activity of the Au monometallic catalysts after addition of Pd, a promotion of the catalysts activity due to the presence of P residues from the ILs and an inhibition of the activity caused by S species. TiO2 supports were also prepared in DES. The use of this IL, in addition to a specific Ti precursor, led to a textural and structural control of the obtained polymorphs (anatase, rutile or anatase-rutile mixture). The influence of the support type was studied in CO oxidation after Au deposition by urea deposition-precipitation. The most active Au/TiO2 catalysts were obtained with anatase-rutile mixtures, the vicinity between anatase and rutile phases leading to an optimum activity and stability.