3D-Printed Silica Aerogels for VOC Degradation
Light-driven thermal transpiration gas pump based on 3D-printed silica aerogels for VOC degradation
In a recent publication (external page Additive manufacturing of silica aerogels, Zhao et al, Nature 584, 387-392, 2020), the authors presented a direct ink writing protocol to create miniaturized silica aerogel objects from a slurry of silica aerogel powder in a dilute silica nanoparticle suspension. Wang’s group was responsible for using the aerogel membranes as a light-driven thermal transpiration gas pump.
Thermal transpiration generates a gas flow from the cold side to the hot side (Fig. a) when a thermal gradient is applied to a capillary with a diameter that approaches the mean free path length of the gas molecules. We printed thin silica aerogel membranes with a top layer containing (black) ramsdellite MnO2 microspheres (Fig. b–e). Upon light radiation, the black-MnO2-bearing side of the membrane heats up, a thermal-transpiration-driven gas flow is established across the membrane (Fig. f), and volatile organic compounds (VOCs; such as toluene) that are part of the gas stream are degraded photothermocatalytically by the MnO2 particles (Fig. g). The work demonstrates the potential of additive manufacturing of silica aerogels and the integration into advanced multi-material architectures.