Nanogold-Containing Catalysts for Low-Temperature Removal of S-VOC from Air

摘要

Activity and selectivity of mono- and bimetallic catalysts containing nano-particles of gold stabilized by different supports are compared in dimethyldisulfide removal from air at 150-320 °C. TiO2-supported Au and Au-Pd samples demonstrate stable and efficient DMDS removal at temperature as low as 155 °C, with formation of the two products: SO2 and elemental S. On the contrary, no formation of elemental S is detected in the case of Au, Au-Rh, and Au-Pd catalysts supported on HZSM-5, H-beta, or MCM-41. The most active Au-Rh/HZSM-5 catalyst demonstrates an efficient DMDS removal at 290 °C, with quantitative DMDS-to-SO2 oxidation. Characterization of catalysts with TPR, XRD, and (XANES + EXAFS) confirms a high dispersion of the metallic phases in all catalysts under study. Specific interaction between nano-particles of gold and titanium dioxide surface could be responsible for the unusual catalytic behavior of Au/TiO2 samples, as distinct from Au/zeolitic systems.