EXAFS study of Pd/Sibunit and Pd–Ga/Sibunit catalysts for liquid-phase hydrogenation of acetylene to ethylene

• A series of Pd and Pd–Ga/Sibunit catalysts with different Pd:Ga ratios were prepared.
• The active component exists in the form of non-stoichiometric Pd–Ga solid solution.
• The addition of large Ga amounts leads to blocking of the active phase by Ga2O3.

A series of catalysts Pd/Sibunit and Pd–Ga/Sibunit were prepared by impregnation with joint solutions of palladium and gallium nitrates in ethanol. The state of the active component and catalytic properties of the samples were studied in the liquid-phase hydrogenation of acetylene. The EXAFS method showed that the active component in the gallium-modified catalysts exists in the form of a non-stoichiometric Pd–Ga solid solution. The activity of the catalysts was found to be determined by the ratio Pd:Ga. It was shown that at the molar ratios Ga:Pd > 0.5:1, the catalytic activity is reduced by blocking the surface of the bimetallic particles by gallium oxide.

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