Catalytic reduction of bromate over catalysts based on Pd nanoparticles synthesized via water-in-oil microemulsion

Supported Pd nanoparticles (NPs) synthesized via water-in-oil (w/o) microemulsion using the water/AOT/isooctane system were used as catalysts in the bromate reduction. In order to study the influence of the support on the catalytic activity, Pd NPs were immobilized on activated carbon (AC), multi-walled carbon nanotubes (CNT) and TiO2. Different thermal treatments in air and nitrogen were carried out in 473–673 K range to modify the supports and also to remove AOT from supported nanoparticles. The immobilization of Pd NPs on TiO2 led to higher activity than the immobilization on the carbon-based supports. Thermal treatment of the catalysts at 673 K in air removed successfully AOT and its decomposition fragments, leading to a significant increase in activity. After removal of AOT, the experiments with catalysts prepared with Pd NPs of different size and supported on TiO2 did not show significant differences in activity. Therefore, no evidence of structure sensitiveness was found.