Title : Synthesis and characterization of catalysts based on Pd-Ni bimetallic nanoparticles
Abstract:
The development of nanomaterials and nanotechnology makes it possible to create new catalysts, which in turn can be successfully used to solve various problems, in particular, for the reductive dechlorination of persistent organic pollutants (POPs) and the production of valuable chemical products from recycled wastes. The currently accumulated stocks of excessively produced halogen-containing by-products and POPs require environmentally friendly disposal, which necessitates the development of methods for the disposal of halogen-containing organic substances and their transformation into less hazardous compounds.
In recent years, the share of studies of the processes of reductive and substitution dechlorination of POPs has sharply increased. In addition, the catalytic reduction method allows you to regenerate the hydrocarbon component of halogenated molecules for reuse, which meets the objectives of resource conservation and the principles of "green" chemistry. The most common catalytic systems used for the reductive dehydrochlorination of organohalogen substances are palladium-containing catalysts on inert supports. The palladium content in such catalysts reaches up to 10%. Therefore, studies to reduce the cost of palladium catalysts due to the "dilution" of the noble metal with other metals with low cost characteristics are a trend in recent years. We carried out work on the development of bimetallic catalysts based on noble nanoparticles (palladium) and transition metals (nickel deposited on birch activated carbon of BAU-Agrade). To identify the features of the formation of active centers of the developed catalysts, various physicochemical studies (SEM, TEM, X-ray diffraction) were carried out. We studied the characteristics and properties of the obtained catalysts using the methods of dynamic laser light scattering, UV spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM),.
The catalysts were black powders consisting of a carbon matrix with Pd-Ni nanoparticles dispersed in it on a carbon support. The microstructure of the support and catalyst were investigated by X-ray diffraction and SEM. According to the results of transmission electron microscopy, the synthesized catalysts consist of isolated Pd-Ni nanoparticles, which are selectively formed on a surface layer up to 200 nm thick. The catalytic systems developed by us were tested for hydrodechlorination of chlorobenzene in ethanol. Preliminary tests established the effectiveness of the catalysts obtained by the method of reducing activated carbon Pd-Cu in the pore volume in the process of chlorobenzene dechlorination, with a yield of conversion products equal to 94.46%.
