The role of hydrotalcite-modified porous alumina spheres in bimetallic RuPd catalysts for selective hydrogenation

• New heterogeneous RuPd catalysts with high dispersion were synthesized.
• Activity for DMT selective hydrogenation was promoted by modified supports.
• RuPd/HTC-Al2O3-1 showed the highest catalytic performances.
• Nanoparticles located in the reticular structure were detected.
• Contributions of structure, morphology and surface properties were considered.

By utilizing alumina previously modified by in-situ growth of varying amounts of hydrotalcites, a series of heterogeneous bimetallic catalysts with constant low loading (0.3 wt.%) and identical Ru:Pd ratio (1:1) were prepared based on co-impregnation for selective hydrogenation of dimethyl terephthalate to dimethyl cyclohexane-1,4-dicarboxylate. Nanoparticles confined in the reticular structure were observed. The resulting candidates show the superior catalytic activity over that supported on the unmodified alumina, and reach the highest in the optimized sample RuPd/HTC-Al2O3-1. This promotion and optimization effect could be ascribed to the improved dispersion and more supply of hydrogen and acid sites especially with medium strength.