An Effective Strategy to Prepare Pd–Ag/MgCO3@α-Al2O3 Catalyst for Selective Hydrogenation of Acetylene

Abstract

A spherical Pd-Ag/MgCO3@alpha-Al2O3 catalyst with highly stable dispersion has been designed and synthesized by an effective in-situ synthetic approach for selective hydrogenation of acetylene. MgCO3 was synthesized in-situ on the surface of spherical alpha-Al2O3 to obtain MgCO3@alpha-Al2O3 support, followed by the introduction of Pd(NO3)(2) and AgNO3. Importing MgCO3 structure offers larger specific surface area to realize uniform dispersion of active constituent Pd, moreover, the synthesized support exhibited the effects on modification of Pd electronic structure and the surface acidity of catalyst. With this Pd-Ag/MgCO3@alpha-Al2O3 catalyst (cat-48) at 70 A degrees C (industrial reaction temperature), acetylene conversion, ethylene selectivity, MAPD conversion, propylene selectivity and n-butene formed can reach 89, 92, 28, 96% and 124 ppm, respectively. In addition, during 500 h long-term test, conversion and selective behaviors of Pd-Ag/MgCO3@alpha-Al2O3 catalyst can basically remain stable. All this catalytic efficiency parameters are superior to Pd-Ag@alpha-Al2O3 (most commonly used in industrial) and Pd-Ag/MgAl-LDH@alpha-Al2O3. We believe that the Pd-Ag/MgCO3@alpha-Al2O3 catalyst with high dispersion of Pd and synergistic effects could be a highly efficient industrial catalyst for selective hydrogenation of acetylene to ethylene. [GRAPHICS] .