Abstract
In this work, Pt nanoparticles were loaded on SiO2, TiOv-thin-film-modified SiOv (TiO2-SiO2), or ZrO2-thin-film-modified SiO2 (ZrO2-SiOv) particles and the composites were investigated for sequential adsorption and desorption/catalytic oxidation of benzene. The SiO2 was prepared via sol-gel method, while TiO2-SiO2 and ZrO2- SiO2 were synthesized via atomic layer deposition (ALD) thin film coating of TiO2 or ZrO2 on SiO2 particles substrate. In the sequential capture-reaction tests, the materials were first exposed to ca. 500 ppmv benzene gas at 25 ? and 1 atm until 5% breakthrough was attained, followed by tandem desorption and catalytic oxidation while raising bed temperature to 200 ?. The benzene vapor adsorption isotherms followed type-IV isotherm classification, revealing a combination of monolayer, multilayer and capillary condensation adsorption mechanisms in sequence. The xPt/ZrO2-SiO2 materials exhibited superior capture-conversion capabilities relative to their xPt/TiO2-SiO2. In particular, 3Pt/ZrO2-SiO2, prepared with 3 cycles of Pt ALD, exhibited the maximum in situ conversion at ~ 100% and turnover frequency of 17.1 mmolC6H6/molPt/s with a dynamic adsorption capacity of 0.45 mmol/g, indicating synergistic effects of Pt nanoparticles and ZrO2 in the ALD-based dual-function materials.