Electrosynthesis of Catalytically Active Nanocomposites of Bimetallic PdCu and PdAu Nanoparticles with Fe(II), Al(III), Zn(II), Cu(I), and Ti(IV) Oxide–Hydroxides

Two-step electrosynthesis of nanocomposites of bimetallic PdCu and PdAu nanoparticles (NPs) with iron(II), aluminum(III), zinc(II), copper(I), and titanium(IV) oxide−hydroxides was carried out in the presence of stabilizer cetyltrimethylammonium chloride (CTAC). In the first step, efficient syntheses of Fe, Al, Zn, Cu, and Ti oxide−hydroxides were carried out by reducing dissolved oxygen or methylviologen and generating metal ions by dissolution the corresponding metal anodes. In the second step, syntheses of bimetallic PdCu and PdAu NPs were proceeded by methylviologen (MV2+)-mediated electroreduction of equimolar concentration of Cu(II), Pd(II), and Au(I) in the presence of CTAC and obtained oxide−hydroxides. The results of the syntheses were nanocomposites of mainly spherical MNPs stabilized with CTAC on the surface of oxide−hydroxides with an average size of 2 to 10 nm, but the PdAu@CTAC/Cu2O nanocomposite showed formation of two NPs types with sizes 7 ± 2 nm (Pd) and 24 ± 10 nm (Au). X-ray powder diffraction data showed the absence of metal crystallites in almost all samples with PdCu due to the amorphous phase, and the presence of bimetallic crystallites with sizes ranging from 1 to 15 nm in PdAu composites. In the test reaction of p-nitrophenol reduction all the tested nanocomposites exhibited catalytic activity.