Evolution of sulfate during the preparation of Pd/Al2O3 catalyst and its effect on the performance of catalytic hydrogenation

During the manufacture of Al2O3, sulfate would be inevitably introduced when aluminum sulfate is used as raw material, but its effect has received little attention. In this work, Al2O3 supports with different sulfate content were synthesized and used to prepare Pd/Al2O3 catalyst. Sulfates in all samples exist as surface sulfate, and would be partially removed during the preparation process. Sulfate existing in Al2O3 supports had little impact on the electric structure of Pd, but would partially block pores and also consume surface hydroxyl groups. As a result, higher sulfate content in support would lead to lower Pd dispersion in catalysts and slower reaction rate towards the hydrogenation of amyl-anthraquinone.