Near-infrared light induced adsorption-desorption cycle for VOC recovery by integration of metal-organic frameworks with graphene oxide nanosheets

Metal-organic frameworks are appealing candidates for adsorption of VOCs from contaminated air due to their outstanding capturing capacities, but the traditional regeneration methods of used MOF adsorbents often suffer from great energy-penalty. Herein, a near-infrared light induced desorption of VOCs from a photodynamic GO@MIL-101 nanocomposite adsorbent was attempted by the integration of MIL-101 with GO nanosheets. MIL-101 uniformly and closely grown on GO nanosheets not only rendered inherent excellent VOC adsorption capability, but also enabled it to manifest strong light-harvesting in the whole UV-vis-NIR region. More importantly, GO nanosheets could serve as "nanoheaters" to convert incident light into thermal energy upon exposure to UV-vis or UV-vis-NIR light, and then the localized thermal energy would rapidly transfer and distribute to MIL-101 located on GO nanosheets, thus making GO@MIL-101 nanocomposites reach higher surface temperatures compared to pure MIL-101 and GO counterparts regardless of UV-vis irradiation or UV-vis-NIR irradiation. Eventually, such light induced localized heat would trigger the complete release of adsorbed ethyl acetate from GO@MIL-101 nanocomposites. Distinct from traditional thermal swing desorption, this light induced VOC release could not only mitigate the drawback of MOF of inferior thermal conductivity, but also would provide a potentially low energy strategy for highly efficient regeneration of MOF-based adsorbents powered by naturally abundant solar light without other energy inputs.