Development of the catalysts for the selective hydrogenation of alkynes is continued in the ZIOC

The selective hydrogenation of acetylene to ethylene is an important industrial process. This is due to the fact that the original ethylene used to produce polyethylene usually contains an impurity of acetylene, which irreversibly poisons metallocene polymerization catalysts. Selective hydrogenation is the most effective method for fine purification of the initial ethylene from acetylene impurities. The ideal catalyst for this process would hydrogenate acetylene in the presence of a huge excess of ethylene with very high selectivity without affecting the ethylene itself. Palladium, which is actively used in organic synthesis as a hydrogenation catalyst, is not sufficiently selective, and hydrogenation of acetylene on Pd catalysts is accompanied by undesirable hydrogenation of ethylene.

Scientists of the Laboratory of Catalysis by Supported Metals and Their Oxides of the Zelinsky Institute together with colleagues from the Boreskov Institute of Catalysis are actively conducting research to find effective catalysts for the selective hydrogenation of various alkynes. One of their latest works is devoted to the development of practical methods for "tuning" the surface structure of Pd-Ag nanoparticles to improve their catalytic performance in the selective hydrogenation of acetylene to ethylene. The experiments performed showed that dosed treatment of the supported palladium-silver catalyst in a CO flow causes segregation of palladium atoms on the surface of Pd-Ag bimetallic particles. Such a controlled change in the surface structure makes it possible to significantly increase the activity of the catalyst while maintaining 100% selectivity. The results obtained prove that CO adsorption-induced segregation is a powerful tool that can be effectively used to control the surface structure and catalytic performance of bimetallic nanocatalysts.

Source:

A.V. Bukhtiyarov, M.A. Panafidin, I.P. Prosvirin, I.S. Mashkovsky, P.V. Markov, A.V. Rassolov, N.S. Smirnova, G.N. Baeva, C. Rameshan, R. Rameshan, Y.V. Zubavichus, V.I. Bukhtiyarov, A.Yu. Stakheev Boosting the activity of PdAg2/Al2O3 supported catalysts towards the selective acetylene hydrogenation by means of CO-induced segregation: A combined NAP XPS and mass-spectrometry study // Appl. Surf. Sci., 2022, 604, 154497. DOI: 10.1016/j.apsusc.2022.154497.